He who doesn't know can do no wrong

I suspect people who have committed wrong-doings, most of them didn’t know what they did was wrong.

A serial killer who killed many may think he did it for liberating the victims’ soul.
A dictator who started war may think he did it for his own people.
A pastor who spent millions of church funds on some outreach projects may think he did it, oh well, because it was the right thing to do.

People who did wrong things without knowing what they did was wrong, I suspect they are the most dangerous.