I read some books by Alice Miller that discussed some childhoods of authoritarian rulers and they were all of unloved. They had not one adult stick up for them, be their advocate or helper, during their childhood years.

Many of us as children have been unwanted or unloved by our caregivers. Most of us had at least one adult: an uncle, grandmother, teacher etc, who truly tried to help at least once.

What the monsters in history had in common is an absence of evidence of even that happening for them. And their revenge as adults was terrible.