Not everyone is brave enough to actually have the courage of their convictions.
That's true, and I totally admit to over-simplifying the situation in my comment.

It just really irritates me that every time anti-Muggle-born prejudice is the topic, everyone is quick to be all "well, ONLY the Death Eaters are prejudiced; the rest of the world is totally cool with it and is not the slightest bit prejudiced! At all!"

And, I mean, I guess it's always been difficult for me to imagine a very small fringe group of lunatics without much demonstrated military power taking complete control of an entire barely-protesting community of magic users. Like, if I could shoot lazors from my eyes (or, even better, restricting spells from my wand) at will, I'd freakin' well shoot them at people who tried to harm me or my family. But perhaps that's just me. >.>

Slughorn is a better example, though, definitely.