Boomers don't understand modern day living.
Military/Veterans are less intelligent and are hate mongerers.
Foreigners who lived under dictators and the like lived under people who didn't know how to make socialism work, are attracted to bullies, don't know how things work here.
Life-Long medical personnel suddenly have no credibility if their perspective doesn't fit the narrative.
It just goes on and on
This is the Dunning-Kruger effect in action. These people don't realize how dumb they are. They think they're so smart that they know everything and could never possibly be wrong.
It's also because liberalism is the rule of emotional thought over logical, and being wrong would make them feel bad or dumb so they are emotionally attached to always being right, to the point of denial of reality.
It really is a mental disorder.