The unexamined aspect of the "all Nazis were filth" slogan is that it tends to go along with an assumption that German Nazis were completely different from the rest of us. The truth is that many, very probably most of us, if we had been living in 1930s Germany, would probably ahve been good little Nazis.

I wouldn't in any way have any problem in saying that in this case "scum" would actually be a fair description of us, but we ought to be careful about assuming that just becauise we are lucky enough not to be in that place and time it still isn't a fair description of how we are.

As has been pointed out, "decent people" seem to have little difficulty in going along with the most apppalling crimes, and just shrugging them off. In that respect, if that is true, we are really no different from the Nazis and the slave-owners. And that doesn't mean they weren't so bad after all, quite the reverse.