Which begs the question: are courage, loyalty and so on actually virtues in their own right, or does their virtuousness depend on other factors? Is there, indeed, such a thing as an absolute virtue, and if not can there be an absolute vice?

The Holocaust was an evil act, perpetrated by people who were probably the usual mix of good and evil in various proportions, some of whom may have genuinely believed they were doing good, at least for the land of their birth. I find it hard to think of them twirling their moustaches and cackling "Generations yet unborn will curse our name for this!" or indulging in the Evil Overlord Cliché of your choice. Pratchett makes a point in Small Gods about the most horrifying tortures of the Omnian Quisition being carried out by men who drank their tea out of mugs with "World's Best Dad" on the side.

I don't think it's as simple as all that...