"We have been cannibals. And we are." 

Speak for yourself, Paravel. I'm not at all sure that the fossil record supports the idea that human beings have, in general, been cannibals. In fact, I think it fair to say that the profound disgust most people feel about the idea is a reflection of how deeply repugnant the idea is to most human beings. And to suggest that we still are cannibals is nothing but a self-serving rationalization. Nothing could be farther from the truth. 

"The idea of retreating from a subject because it makes us uncomfortable seems to me very cowardly". So.....what next from the great Paravel who qualifies himself to sit in judgement of the human race? Kiddie porn? 

The reason disgust exists is to serve to protect our souls from avoidable contamination. If I choose to avoid your disgusting film, it is not because I am a coward but because I don't care to pollute my experience with offensive imagery and rationalizations.