There's a strange pattern of die hard obstinence, even in the face of basic and common facts that we as as society until fairly recently all agreed upon. The reason is that works, if you admit fault/guilt then the usual consequences follow. If they remain obstinate, there's a chance they can project their crime on someone else which doesn't really work except it does retain for them a certain level of public support, from those who "see" what they want to see.

It's devastating society.

The tricky part is that people don't necessarily report what they see as what they see, and you can't really look inside their brains to get at what they meaningfully perceive.

A good example of this was the inauguration crowd size photos where people who were unfamiliar with the topic reported a unified perception on which crowd was bigger based purely on the photos. People who knew what the photos were of varied their conclusion based upon their political stance.

One conclusion you could draw from this is that their beliefs were altering their perception, but how would you distinguish that from people altering their expression of what they saw based upon their beliefs?

That basketball gorilla experiment seems like pretty solid evidence that people only notice what they expect to see and are primed to pay attention to, even in situations with no ideological component.