Carlo Cipolla knew the answer to your question. https://en.m.wikisource.org/wiki/The_Basic_Laws_of_Human_Stupidity

And “good” vs “evil” is relative anyway. Even someone like Hitler would have believed he was doing something for the better good, even if it was a completed twisted view. For me, what is important is internal self-consistency. Do you have a reasoned position and hold on to it? Then you are probably not stupid.