Hmm. I might would agree that it's natural in the sense that children end up learning it anyway because their interactions with others force them to. If a child wrongs someone else, that someone else is going to snap back somehow, which will cause the child to try to understand why.

But I can't really agree that it's hardwired into our brains. How do you explain spoilt children then? I think it's widely accepted that if you protect a child from the consequences of their actions too fanatically, you end up with a vicious and completely self-centered brat.

As for sociopathy broadly being a mental disability, I couldn't disagree more. I wrote quite a long paragraph on this before I realized it was going to branch us way off-topic. Suffice to say, I consider complete amorality to be perfectly viable in a person. I wouldn't live that way myself, but I can see the benefits and the downsides. I consider it more viable than perfect morality as well. The negative attitude towards sociopaths, psycopaths, or whatever you want to call an amoral person is just a reaction by society towards a state of mind that is a threat to them. It's bad for us as a group, therefore we don't like it.