Why are the Weasleys specifically considered blood traitors?

Question

There are a lot of wizards that are not only okay with Muggles, but even marry them (say, Tonks' mother, for example). Actually, apart from such intense cases as the Blacks, Malfoys, Lestranges etc., a lot of wizards seem to be at least tolerant to Muggles. There are known cases when wizards helped their Muggle neighbors or protected them.

Still the whole Weasley family is the one targeted with this "blood treachery" stigma more than the others. They preserved their blood line as pure (unlike many other families) and there is only one family member (Arthur) who can be seen fascinated with Muggle technologies, which is seen more like being a weirdo, rather than aggressive Muggle defender.

What is their treachery exactly that is seen by the pure-bloods as something outstanding?

Answer 1

Because they were listed as one of the "Sacred Twenty-Eight".

In the early 1930s, a ‘Pure-Blood Directory’ was published anonymously in Britain, which listed the twenty-eight truly pure-blood families, as judged by the unknown authority who had written the book***, with ‘the aim of helping such families maintain the purity of their bloodlines’.

There are not as many true pure-blood families as you might expect, or at least not many that can trace their lineage that far back.

The Weasleys specifically decried their name being included on the list from the start:

A minority of these families publicly deplored their inclusion on the list, declaring that their ancestors certainly included Muggles, a fact of which they were not ashamed. Most vocally indignant was the numerous Weasley family, which, in spite of its connections with almost every old wizarding family in Britain, was proud of its ancestral ties to many interesting Muggles. Their protests earned these families the opprobrium of advocates of the pure-blood doctrine, and the epithet ‘blood traitor’. Meanwhile, a larger number of families were protesting that they were not on the pure-blood list.

_{All quotes are from Pottermore.}

Answer 2

The Weasleys are odd as they’re a whole family of blood traitors.

Blood traitors are pure-bloods who don’t care about being pure-blood, which is why they’re called ‘blood traitors’ - they’re betraying their pure blood by choosing not to value it, making them traitors to their blood status. The only particularly unusual thing about the Weasleys is that they’re an entire family of blood traitors - since being a blood traitor requires both not valuing being pure-blood while still actually being pure-blood, it doesn’t usually come in whole families like that. The Weasleys are known so much as a family of blood traitors that no Weasley would be on the Black family tree.

“The pure-blood families are all interrelated,’ said Sirius. ‘If you’re only going to let your sons and daughters marry pure-bloods your choice is very limited; there are hardly any of us left. Molly and I are cousins by marriage and Arthur’s something like my second cousin once removed. But there’s no point looking for them on here – if ever a family was a bunch of blood traitors it’s the Weasleys.”
_{^{- Harry Potter and the Order of the Phoenix, Chapter 6 (The Noble and Most Ancient House of Black)}}

The Weasleys being known as a blood traitor family predates Arthur - Cedrella Black, who’d have to have been born between 1915 and 1919 based on her elder and younger sisters’ birth years, was blasted off the tree for marrying the blood traitor Septimus Weasley.

It’s rare to have a family of blood traitors, as they’d have to not value their blood status but still have kept their bloodline pure. To be a blood traitor, the wizard first has to be a pure-blood themselves. Typically, a blood traitor will go marry someone that’s not pure-blood, and then since their bloodline is no longer pure, their descendants would no longer be considered blood traitors because they don’t have pure blood to be traitorous to. Muggle-loving wizards who aren’t pure-blood aren’t called blood traitors, they’re called other things. Harry, who’s not a pure-blood because his mother was a Mudblood, isn’t called a blood traitor, he’s described as having no proper wizard feeling instead.

“Saint Potter, the Mudbloods’ friend,’ said Malfoy slowly. ‘He’s another one with no proper wizard feeling, or he wouldn’t go around with that jumped-up Granger Mudblood.”
_{^{- Harry Potter and the Chamber of Secrets, Chapter 12 (The Polyjuice Potion)}}

Dumbledore is also a half-blood like Harry, and though he’s called a Muggle-lover, Mudblood-lover, and various other things because of his views, he’s not a blood traitor because he’s not pure-blood.

Blood traitors are pure-bloods who don’t value their blood status.

The Weasleys, like other blood traitors, are called blood traitors because despite being pure-bloods themselves, they don’t actually value being pure-blood or think Mudbloods and Muggles to be beneath them - they’re traitors to their blood by not valuing their blood status. Draco Malfoy, a pure-blood himself, sums up fairly well what about the Weasleys makes them blood traitors.

“Arthur Weasley loves Muggles so much he should snap his wand in half and go and join them,’ said Malfoy scornfully. ‘You’d never know the Weasleys were pure-bloods, the way they behave.”
_{^{- Harry Potter and the Chamber of Secrets, Chapter 12 (The Polyjuice Potion)}}

The Weasleys are all blood traitors, not just Arthur, because Arthur isn’t the only Weasley with blood traitor views. All the Weasleys, including the children, clearly show that they share his views - Ron tells Harry that blood status doesn’t matter at all.

“There are some wizards – like Malfoy’s family – who think they’re better than everyone else because they’re what people call pure-blood.’ He gave a small burp, and a single slug fell into his outstretched hand. He threw it into the basin and continued, ‘I mean, the rest of us know it doesn’t make any difference at all.”
_{^{- Harry Potter and the Chamber of Secrets, Chapter 7 (Mudbloods and Murmurs)}}

However, the Weasleys aren’t the only ones. There are blood traitors other than the Weasleys, as well - Sirius Black was a blood traitor because he didn’t think being a Black meant anything.

“Yoooou!’ she howled, her eyes popping at the sight of the man. ‘Blood traitor, abomination, shame of my flesh!”
_{^{- Harry Potter and the Order of the Phoenix, Chapter 4 (Number Twelve, Grimmauld Place)}}

Sirius tells Harry how he hated his family and the way they valued their blood purity - he’s also a blood traitor because he’s betraying his pure blood by choosing not to value it.

“Because I hated the whole lot of them: my parents, with their pure-blood mania, convinced that to be a Black made you practically royal … my idiot brother, soft enough to believe them … that’s him.”
_{^{- Harry Potter and the Order of the Phoenix, Chapter 6 (The Noble and Most Ancient House of Black)}}

Though we don’t actually see her being called one, Andromeda Tonks would also be a blood traitor as she was a pure-blood who actually married a Mudblood and reproduced with them.

“Andromeda’s sisters are still here because they made lovely, respectable pure-blood marriages, but Andromeda married a Muggle-born, Ted Tonks, so –’ Sirius mimed blasting the tapestry with a wand and laughed sourly.”
_{^{- Harry Potter and the Order of the Phoenix, Chapter 6 (The Noble and Most Ancient House of Black)}}

The Weasleys are all blood traitors for the same reason everyone else called blood traitors are called it - they’re pure-blood but don’t value their blood status.

Most pure-blood families aren’t blood traitors as they do value it.

The reason the Weasley name itself is associated with being blood traitors while the names of other pure-blood families aren’t is that none of them have all stopped valuing their blood purity in the same way that the Weasleys have - the blood traitors would be a minority in an otherwise proper pure-blood family. As the Dark Lord says, it’s considered more like a small diseased part on their family tree, but the rest of the family are still worth protecting as proper pure-bloods.

“Many of our oldest family trees become a little diseased over time,’ he said, as Bellatrix gazed at him, breathless and imploring. ‘You must prune yours, must you not, to keep it healthy? Cut away those parts that threaten the health of the rest.”
_{^{- Harry Potter and the Deathly Hallows, Chapter 1 (The Dark Lord Ascending)}}

One blood traitor in a pure-blood family doesn’t mean the whole family are thought of as blood traitors regardless of their behavior. The Weasleys are different because they’ve all decided to not value their blood status as a family, and there doesn’t seem to be any Weasley who behaves like a proper pure-blood. This is why the Weasley name is more associated with being blood traitors than any of the other pure-blood families, and why any Weasley whose views are unknown would be presumed to be a blood traitor because of their family name unless they prove otherwise.

Answer 3

They're not actually shown to be more blood traitorous than others

I think the answer to this question may be that its premises are not entirely correct. If we look through the books we don't actually find that the Weasleys are specifically targeted with the blood traitor stigma.

There are only two other people that are explicitly referred to as blood traitors in the books:

• Sirius Black

"Yoooou!" she howled, her eyes popping at the sight of the man. "Blood traitor, abomination, shame of my flesh!"

• Merope Gaunt

"You disgusting little Squib, you filthy little blood traitor!" roared Gaunt, losing control, and his hands closed around his daughter's throat.

The Weasleys are mentioned as blood traitors a little more than a dozen separate times. However, we have to account for selection bias here. Even if there were a hundred other families that were as equally blood traitorous as the Weasleys, we would expect to hear it much more about the Weasleys because the Weasleys are main characters. Since we are exposed to them all the time throughout the books it is logical to assume that we would hear about their traitor status much more than we would hear it about other peripheral characters.

For example, the majority of mentions of the Weasleys being blood traitors are the ravings of Kreacher and the portrait of Mrs. Black. This is perfectly understandable because the Weasleys are the blood traitors that are always present in Grimmauld Place (or at least present whenever the reader is present).

Similarly, there are a few other mentions that are perfectly understandable in this light:

• Slytherin Seeker Harper refers to Ron as a blood traitor.

"Thinks he's something special today, doesn't he?" said a snide voice, and Harry was nearly knocked off his broom as Harper collided with him hard and deliberately. "Your blood traitor pal..."

This was not a conversation about blood traitors. It was simply a Slytherin trying to annoy Harry and insult his best friend so he used the best insult a Slytherin could come up with and called Ron a blood traitor. If Harry had happened to be best friends with someone else who came from a family with pro-Muggle leanings, Harper likely have said the same thing.

• Zabini calls Ginny a blood traitor.

"I wouldn't touch a filthy little blood traitor like her whatever she looked like," said Zabini coldly, and Pansy looked pleased.

Here, too, it was not a conversation about blood traitors. Zabini was simply explaining why he wouldn't like Ginny no matter how good-looking she was. To that end he says the most negative thing about her he can think of, namely, that she is a blood-traitor. Had they been talking about a different girl from a pro-Muggle family, he would probably have said the same thing.

• Pius Thicknesse refers to Mr. Weasley as a blood traitor.

"Ah, well. It's only a matter of time," said Thicknesse. "If you ask me, the blood traitors are as bad as the Mudbloods. Good day, Runcorn."

Once again, this was not a conversation about blood traitors. It was a conversation about Mr. Weasley, and Thicknesse was merely expressing his opinion of him. Had they been talking about someone else, Thicknesse would likely have said the same thing.

• Fenrir Greyback refers to the Weasleys as blood traitors.

"A Weasley?" rasped Greyback. So you're related to blood traitors even if you're not a Mudblood.

Here as well it was not a conversation about blood traitors. Greyback was just mentioning the fact that a prisoner that he caught is related to blood traitors, which may be something he would get rewarded for.

• Bellatrix calls Ron a blood traitor.

"If she dies under questioning, I'll take you next," she said. "Blood traitor is next to Mudblood in my book.

This too is not a conversation about blood traitors. Bellatrix is simply using a standard pure-blood insult, and explaining why she would pick Ron next.

In short, the reason it seems like the Weasleys are targeted so much is merely that, as the readers, we are hanging out with the Weasleys so much.

Note that in all of the above instances, the "bad-guys" never stated or implied that the Weasleys are more blood traitorous than any other blood traitors.

This brings us to the three statements made by the "good-guys".

Sirius says:

But there's no point looking for them on here — if ever a family was a bunch of blood traitors it's the Weasleys.

And Ron says:

"My whole family are blood traitors! That's as bad as Muggle-borns to Death Eaters!"

And he says:

"It was always a matter of time, Dad's been saying so for months. We're the biggest blood traitor family there is."

Here we finally see the perception that the Weasleys are somehow especially blood traitorous. However, there are several points to make. Firstly, these are the "good-guys". They may not be accurately informed as to how the "bad-guys" rank their blood traitorousness.

Secondly, they may be simply exaggerating.

Most importantly, though, even if they are correct and literal, the particular egregiousness of the Weasleys' blood traitorousness may not be that they are worse blood traitors, but simply that there are more of them.

Any pure-blood family can have one bad apple. When they do, the family can simply blast them off the family tree and forget about them. But with the Weasleys its not just one deviant family member who challenges the pure-blood beliefs. Its the entire family (clan?) that rejects them. Thus, the Weasleys are somewhat unique in that they are a whole group of blood traitors, even if there traitorousness is not inherently worse than anyone else's.

In each of the three above quotes, it is specifically mentioned that they are a family of blood traitors. This may be the reason — if it is true at all — that the Weasleys are looked at as different from other blood traitors.