I think the claim that Dasein has to do with Nazism would need to be demonstrated. I think for any idea it is reasonable to assume it doesn't have anything to do with Nazism until demonstrated otherwise. Dasein's throwness, so far as I can see, doesn't have anything to do with Nazism.

Of course there is always the possibility for any idea that it leads to death camps. But it is rather hard to exhaustively explore the consequences of anything.

It could well be, however, that having an affilation with Nazism increases the likelihood that your ideas lead to death camps. Although even that ought to be deomnstrated rather than assumed.

For an idea in general, sure. But Heidegger literally joined the Nazi party and never repented publicly. So there is a burden of proof on the ideas he specifically created to show that his Nazism was unrelated and accidental to the idea.