You can't dehumanize someone and claim to understand them simultaneously. It's logically incoherent to draw a conclusion from a failure to understand.

When I try to understand people, I start by assuming that they, like everyone, have an inner self with the golden rule hardwired at a very basic level, and anything appearing to violate that is an illusion creating by coping behavior, distortions in perceptions, or something. Psychic pain being prioritized over everything else can make the resulting behavior very confusing.

Also, since I'm not a professional psychologist I don't have to pretend I understand when I don't.