I mean, no offence, but you can use that line of reasoning to explain away literally anything.
“Because the world is so much easier to comprehend when you convince yourself all people are just naturally good, and thus can always be saved.”
I was born and raised with a psycho, I really wished for the longest time that my sibling was normal and just acting out. I guess having first-hand experience with a sick person will erase someone’s doubts real quick.