I'm afraid some immunity far more powerful than our belief system, my friend, no matter how ugly this truth is! It's called character-disturbance, troubled souls who lost their battle and turned not only bad but EVIL. They have a clinical name: malignant narcissists and psychopaths (whether displaying antisocial traits or not. The latter are more dangerous, btw. Unlike the impulsive former, they are very calculating; thus, are never held accountable for their horrific psychological crimes against humanity). Those evil people don't feel remorse or guilt or empathy at all. Completely disconnected from their conscience, all that they may feel is emptiness and bitterness.