What's wrong with cannibalism?
If you were starving, hanging on to the last vestiges of life, and you're only hope of survival was to consume the meat of humans who had already died, would you not do so?
I would. It's only natural, after all, because the instinct of survival is far more powerful and encoded far deeper in our genome than any artificial sense of "morality" or "ethics". Even the chimpanzee, our evolutionary cousin and a creature whose DNA sequence is 99.7% identical to that of humans, resorts to the cannibalism of their young when they fail to survive past infancy.