I read that the Aztecs practiced human sacrifice and cannibalism because their diets were protein-deficient. However, their extreme acts would indicate something else. Were they demons, aliens, greys, maybe we will never know, except for the fact that this stuff still happens. The stories on the history channel almost try to make it all sound ok. The victims went readily to their deaths, because it was an honor or they sacrificed mostly only enemies.
Oh I see, that made it ok.