Oddly, the exact nature of German anti-Semitism is not something I know much about despite a lot of reading on the Holocaust, but wasn't a lot of it the idea that the Jews were out to get the non-Jewish Germans; that they were not merely a lower race (whatever that means) but actively evil and plotting the downfall of everyone else?

If you think people are out to get you, I'm not surprised that you'd want to get them first. I see a lot of this going around right now, actually.