I have a difficult time labelling anyone evil no matter how horrific their actions. Even Hitler and any of the others mentioned as evil or having done evil acts had people in their lives who loved them. I think we are all multi-dimensional human being, each capable of doing good and evil. Born to survive. Conditioned how to survive. The journey determines the process and outcomes. Biology and genetics may factor in but circumstances and conditions can over ride either of those.

It seems to me one would have to be born evil in order to be an evil person. I can't imagine any baby is born evil. As we grow up we make choices to do harm or to not do harm. We control our choices but we are influenced to one degree or another by factors they may sometimes be, or at least feel outside our control. It is a matter of degree that may mark the line over into what people consider 'evil'.