Moral relativism is a black hole. It's hard to say the actor in one atrocity is better or worse than another actor in another atrocity. But I think it could be said that the Aztec civilization was complicated, and of which the kidnap and brutal sacrifice from its neighboring tribes was one (rather sensationalized) aspect. And I've said it elsewhere, but the podcast really gives you a sense of what it was like to live in the place and time - as much as one can from researching the extant artifacts.