I didn't see the movie either, I'm just going on things I read about it. I wrote a thing after OotP about how the Slytherins seemed a bit like anti-Semitic stereotypes then (while of course also being Nazis, because you can't be evil without that!). I don't think that JKR is saying anything anti-Semitic--they're not "really" Jews or anything. But in terms of their place in the scheme of things, they seemed to fulfill the same type roles. I wonder how they manage to fill up a quarter of the school with them.

I guess I shouldn't really be surprised by Harry casting Unforgivables, since Harry's personal character was never ever in doubt. Dark Magic just bounces right off him, really.