These matters are tricky because (in an obvious statement of reality) it’s difficult to know for certain what’s exactly happening inside the mind of others. We do our best to figure it out by making conjectures and hypotheses based on the internal investigation of self and the external observation of others, but even then we’re ultimately guessing, no matter how strong that guess may be.
And to take this pondering in a somewhat different direction, what if we were to use a time machine and visit baby Hitler? What would be the proper way to approach an innocent little baby that would go onto to become a villain to humanity? Should we pull a Minority Report and convict him before he commits his crimes? Or should we take it upon ourselves to try to teach baby Hitler a different way, an alternative lifestyle based on the principles of love and kindness? How far can teaching go? Was it written into his DNA to become a diabolical force regardless of circumstance?