It would take quite a lot to really delve into this issue, but “evil” isn’t something that a person can be (ontology) but something you do. It’s a matter of actions, not a state of being. Moral essentialism is pretty untenable so far as I’m concerned. Of course, I’m not saying that if people consistently behave in a way that we consider bad, they aren’t likely to continue to behave that way. Chances are, if circumstances and environment remain the same, so will they. (Though then again, not always). But that’s a far cry from claiming some people are innately evil.