Did Pius Thicknesse have blood purity sympathies?

Question

We know that Thicknesse was under the Imperius curse when he was installed by Voldemort as Minister of Magic, and thus his actions may have been caused by DE orders.

But this conversation from Deathly Hallows is very strange:

Thicknesse: "What brings you here, Runcorn?"
Harry: (in the guise of Runcorn) "Needed a quick word with Arthur Weasley. Someone said he was up on level one."
Thicknesse: "Ah. Has he been caught having contact with an Undesirable?"
Harry: "No. No, nothing like that."
Thicknesse: "Ah, well. It's only a matter of time. If you ask me, the blood traitors are as bad as the Mudbloods. Good day, Runcorn."
Harry: "Good day, Minister."

OK, I can believe that he was Imperiused to issue various decrees.

But I cannot believe someone went to the trouble of Imperiusing him to spout the Blood Purity Party Line when talking to a fellow pro-Voldemort Ministry Employee.

Did Thicknesse (before being Imperiused) hold the same pro-Blood-Purity views?

It's not exactly unusual in a high level Ministry official - witness the Wicked Witch of the Pink err... toadface err... Fudge's Senior Undersecretary Umbridge and her Nazi-like views. Or the fact that Fudge was a lot closer politically to Malfoy than Dumbledore.

_{Canon information only please: books/interviews/Pottermore}

Answer 1

Wow, this is a great question, one that's hard to answer. Regarding Pius Thicknesse, it's possible that he was not driven by blood purity laws or beliefs. In Deathly Hallows, Yaxley says this about Thicknesse:

Once again, all heads turned. Yaxley squared his shoulders. ‘My Lord, I have good news on that score. I have – with difficulty, and after great effort – succeeded in placing an Imperius Curse upon Pius Thicknesse.’

_{Deathly Hallows - page 12 - Bloomsbury - chapter one, The Dark Lord Ascending}

On the next page, Voldemort says of Thicknesse:

‘As long as our friend Thicknesse is not discovered before he has converted the rest,’ said Voldemort

_{Deathly Hallows - page 13 - Bloomsbury - chapter one, The Dark Lord Ascending}

Thicknesse was Head of the Department of Magical Law Enforcement when he was placed under the Imperius Curse. The fact that he had to be placed under the Imperius Curse at all indicates that he was not a blood purist. Yaxley notes that it was extremely difficult to curse Thicknesse to begin with. When Barty Crouch Jr as Mad-Eye Moody teaches the fourth years the Imperius Curse in Goblet of Fire, he reiterates that the Imperius Curse can be resisted. So to put the Head of Magical Law Enforcement under the Imperius Curse must have been a tremendous feat. It has to do with the reason behind the Imperius Curse, i.e. why the Death Eaters wanted to control him.

It's clear the Death Eaters wanted Thicknesse to help turn other Ministry officials (and whoever else) to their agenda, which included blood purity. That they needed to use the Imperius Curse at all indicates that Thicknesse was not a blood purist prior to begin with.

What's not clear is when, or if, the Imperius Curse was lifted. Thicknesse fights alongside the Death Eaters at the Battle of Hogwarts -- does this mean he's still under the control of the Death Eaters, or does it mean he's been on the Death Eaters' side all along?

I say he was under the Imperius Curse when he said the quote you've highlighted in your question. That was the whole point of putting him under Imperius to begin with: 1) He was needed to convert non-believers to the blood purity line of thinking and 2) Voldemort needed a puppet to cover the fact that he was indeed controlling the Ministry and politically speaking, it makes sense that the Head of the Department of Magical Law Enforcement would be poised to become the next Minister for Magic -- as Barty Crouch Sr was set to do before his son was outed as a Death Eater -- which may be why the Death Eaters specifically wanted Thicknesse under their control.

No, Thicknesse was likely not a blood purist when he was placed under the Imperius Curse.