Exposure to people of other races can help a lot, but racist beliefs can be durable, especially with some kind of reinforcement from the likes of Tucker Carlson et al. A person can find a way to reconcile positive interactions on an individual level with beliefs about races as a group. They can think that people they have met are exceptions that prove the rule, i.e. “one of the good ones” or a “credit to your race,” etc.
As I mentioned in my other story in Human Parts, my youth pastor said “There are black people and there are ‘n-words.’” (he actually said “n-words” because he didn’t want to seem racist.) There are also other slang words I’ve observed studying hardcore white supremacists, like IKAGO (I Know A Good One) and NAXALT (Not All X Are Like That).
Ben Carson was actually Dad’s first choice in the 2016 primary, then Scott Walker, then Ted Cruz and finally Trump. You can make of that what you will. I do think having black neighbors has helped Dad a lot, but he’s still generally hostile to Muslims and gets caught up in all the racist scaremongering about MS-13, etc.