You’re confusing understanding the roots of a behavior with saying a behavior is OK. If we want to prevent future Hitlers, future Boston Marathon Bombers, etc, we *have* to do more than just morally condemn the people who did those deeds — we have to look at the external factors that make those deeds more common and more likely. That doesn’t give any of the people who committed those deeds a moral pass. It’s a totally separate issue. I’m interested in the pragmatics, in preventing future harm. How evil I feel something is doesn’t matter, it’s just a feeling.