This might come as a surprise to all of you, but humans are even more uncivilized than most of you have believed so far. For unexplainable reasons, besides weird barbaric culture, humans detest the idea of consuming another of their species.
They don't understand the concept of internalizing their loved ones and bringing them along. Consequently, they also delay the advancement of their species due to ignoring the physical and mental improvements which come as a byproduct with these sacred acts.