Exodust does bring up a really good point and something ive thought about. Serial killers or people that can commit some terrible shit do get some form of empathy from me. In the the sense that those desires or feelings are most likely biological, or the right environmental shit happened to trigger those desires on a biological level.
That being said, you gotta own up to what you are no matter what. If youre born a monster or fucked up, you can either find the will to change and not give in, or you own up to being a monster and accept whats gonna come to ya. Life isnt fair to normal people, sure as shit wont be fair to people that fuck up normal lives.