Actually "moral relativism" is more or less the reverse of how I see the world. All kinds of evil things are seen as good things by the people who do them, and may be seen as good things by the people around them as well, and by whole societies for that matter.

A moral relativist would say that this meant that it'd be wrong to call such things "evil". I wouldn't. I wouldn't necessarily feel entitled to call the people involved "evil", but that's a very different matter.