Wikipedia says:

Cannibalism has recently been both practised and fiercely condemned in several wars, especially in Liberia[10] and the Democratic Republic of the Congo.[11] It was still practised in Papua New Guinea as of 2012, for cultural reasons[12][13] and in ritual as well as in war in various Melanesian tribes. Cannibalism has been said to test the bounds of cultural relativism because it challenges anthropologists "to define what is or is not beyond the pale of acceptable human behavior".[1] Some scholars argue that no firm evidence exists that cannibalism has ever been a socially acceptable practice anywhere in the world, at any time in history, although this has been consistently debated against.[14]

So I suppose it's up for debate even though it seems there's evidence for it. I don't know much about the topic.