They have lost all ability to remember the past.
Big head political pundits literally go on Fox News and blame a Democrat President for Epstein's death, and you have to tell them "Uh, no, Trump was president then, and it was his administration in control" and they have this insane double take look like they can't possibly remember that.
Blaming Obama for the Hurricane Katrina response wasn't a fluke.
My father is a general contractor and viscerally experienced Trump's first term stupidity tripling his material costs. He still voted for him again, as "good for the economy", or "the democrats have gone too far". He blames democrats for the regional grocery chain hiring gay people as managers, which is funny, because they hire those people because they are the right kind of MBA types. He literally can't recognize the problem when it's in his very face.
My father has never been outwardly sexist and always demonstrated respect for strong women and their ability to participate in normal society. He still was convinced by right wing media that he should be afraid of women in the cockpit.
The soybean farmers were fucked by Trump's first term, and he gave them over $10 billion dollars. They all voted for him again, and it happened the exact same way.
Like, at this point, how do you convince people who change their memory of reality to fit their ideology?