Malformed brains, maybe? I read something that a scientist posted about Trump possibly having a form of Antisocial Personality Disorder that comes from having a weird brain that actually lacks the ability to have feelings like empathy and such.

I've come across so many people that are malignant narcissistic sociopaths who are so terrible (despite having only slightly bad lives at best combined with an extreme amount of privilege) that I have actually wondered if there's something physically wrong with their brain / body.

Definitely have theorized that if this is the case, it tends to particularly associate with the Y Chromosome because it's mostly men that display this kind of behavior.