Their stupidity and ineffectuality are our only defense against tyranny.
I believe it is called cognitive dissonance. When your existence is tied to a belief or sometimes a person it is very hard, even with proof, to change you positions.
Though not quite the same, as they admitted they had proved themselves wrong, the left is very much like this. They will never admit anything they believe is wrong, to do so would mean they would have to look at all their beliefs which may also be wrong, they never will and their responses to facts are always the same racist, nazi ,some sort of phobic……
One guy took a flat farther up in a high altitude ballon, the guys response “I did not see enough of a curvature to change my mind. Wonder if even a trip into space would change his mind
That is how powerful beliefs can be