I think people are bad people because they choose to be. Sure there can be causes for anything and why is that? Simple if you look for a reason you will always find a plausible one. Doesn't make it right just means you found something believable.<br />
I believe people who are bad decided on that on their own. They understand what other people think about what they do or think. They know other people think things are bad or wrong but they don't care. They might not understand fully why something is wrong but they know they are told it is wrong. So ultimately it is their choice in my opinion.
I'm not sure what you mean by "bad people" - there are degrees of bad I think we can all agree. I would have to say Yes, but only if actually suffering from a mental disease or defect.
Or anyone named Michael or Kayden, Aiden, Hayden or Jayden.....sweet Moses!
There have been some serial killers with messed up genes that are a marker for such behavior.
Sociopaths, right? The idea that sociopathy is genetic is far from certain, they really have little idea how that happens. In any case, the sociopath is generally rational, of above average IQ, and perfectly capable of adopting a moral code should they choose to do so - they merely lack conscience, but there are moral codes based on rationality and other ideals that one can adopt. Also all children need to be taught why it is wrong to cause harm to others (young children are completely incapable of empathy and some take a long, long time to develop it and continue to be very limited in terms of it), so it is more the choices after the reward-punishment stage that matter.