"Sympathy for the Devil"
Meso-American cultures (yes, even highly advanced ones) also didn't let the protein go to waste -- if you know what I mean. Forensic studies on bones confirm early Spanish descriptions of ritual canibalism.
A.k.a., cultural relativism. Apparently that great Prophet and Priestess Margaret Mead wouldn't approve of this movie either. Brutality is A-OK, as long as it's a part of a non-Judeo/Christian culture.