Why does Hermione claim that all wands are equal, save for the Elder Wand?

Question

In Harry Potter and the Philosopher's Stone, Ollivander and Harry have this conversation:

‘Ah yes,’ said the man. ‘Yes, yes. I thought I’d be seeing you soon. Harry Potter.’ It wasn’t a question. ‘You have your mother’s eyes. It seems only yesterday she was in here herself, buying her first wand. Ten and a quarter inches long, swishy, made of willow. Nice wand for charm work.’ Mr Ollivander moved closer to Harry. Harry wished he would blink. Those silvery eyes were a bit creepy. ‘Your father, on the other hand, favoured a mahogany wand. Eleven inches. Pliable. A little more power and excellent for transfiguration. Well, I say your father favoured it – it’s really the wand that chooses the wizard, of course.’

Later in the same chapter, Ollivander says this:

‘I’m sorry to say I sold the wand that did it,’ he said softly. ‘Thirteen and a half inches. Yew. Powerful wand, very powerful, and in the wrong hands … Well, if I’d known what that wand was going out into the world to do …’

This contradicts the claim that "wands are only as powerful as the wizards who use them. Some wizards just like to boast that theirs are bigger and better than other people's." Hermione says this. The Elder Wand is obviously exempted from this statement. Where does it say that all wands are equal in power, save for the Elder Wand? Why does Hermione claim that all wands are equal, save for the Elder Wand?

Answer 1

The claim that "wands are only as powerful as the wizards who use them. Some wizards just like to boast that theirs are bigger and better than other people's” is a general colloquialism not intended as universal law of wizarding. Her first sentence lacks any qualifier, including for example, an implied “(all) wands…”

However, it is a universal law of wizarding that all wands are equal — at least in sense that the wand is only as powerful as the wizard — except the Elder Wand. The Elder Wand is more powerful than the wizard.

Also, Ollivander is a salesman, and is using tried and true sales practices in that scene to sell his products; this is immediately clear in his mixed message about Harry’s father’s wand — did Harry’s father favor it, or did the wand pick him? Or both? It doesn’t matter to Ollivander or being factually correct because Ollivander is telling the tale to help make a sale. Ollivander’s later statement doesn’t contradict the concept of being as powerful as the wizard: the wand fell into the wrong, powerful hands and so was powerful because the wrong-handed wizard was powerful. The general description on wands is maintained.

Answer 2

I believe that this is not the correct interpretation of Hermione’s statement. She was not saying that there is no difference in wand power except for the Elder Wand. On the contrary, she was specifically referring to the Elder Wand. The context of this statement is when Harry, Ron, and Hermione were discussing what Xenophilius Lovegood had just told them about the Deathly Hallows, one of which is the Elder Wand. Hermione rejected the concept of the Deathly Hallows, saying that there could be no Elder Wand, and wands are just as powerful as the wizards wielding them. Of course, it later turns out that Hermione is incorrect about this, at least to the extent that the Elder Wand is shown to exist later in the story (though one could perhaps argue that the advantage of the Elder Wand is mostly psychological).

Given the above, it would be unsurprising if there were also differences between regular wands, and that Hermione was unaware of that. As Ollivander notes, wandlore is a pretty obscure branch of magic and there is a lot that is unknown.