So if we assume that the idea of morality is to create social-order, the idea that eating other people would be 'right' just wouldn't add up.

Actually it does. The reason cannibalism prevailed in some cultures was because people saw that it empowered them. In times where food was scarce (humans were mostly scavengers) eating fresh meat did give them more energy. I also mentioned Inuits in the example that eat their babies in case of a harsh winter.

If the planet was really hard to live then cannibalism would be perfectly moral. Morality is almost always bound to environmental constituents.

I imagine the small percentage of people whom are purely evil are the psychopaths [and potentially sociopaths] but more so psychopaths who generally feel pleasure at the suffering of others....

psychopathy might be a circular condition. those who have been abused or suffered a lot, simply turn off. (form of existential pathology)