They are still racist pricks. The ones at church are just the “good ones” who do a good enough job of code switching - ie so the racists say “you’re not like most Black people”.
(yes I’m Black).
This guy is famous for converting kkk members by just showing them that they can be friends with a black guy. They didn't just write him off as 'one of the good ones', it undermined their fundamental racist beliefs.
At least that's how I see the "nuanced racists" in my life (I'm white, fwiw, so it's not the other side view you were probably looking for).
I say this specifically because the one truly effective intervention we know of that can destroy bigotry is getting to know someone of the group they are bigoted against. My layman's guess as to what makes the difference between someone who just labels the black/queer/etc person they know as "one of the good ones" and someone who actually starts to change is whether a) the former are personal friends with the latter, and b) the latter is willing & able to speak up and say "just making an exception for me is kinda shitty, other people like me aren't bad either, and if you keep talking about them like that I won't be able to stay your friend".
They don't change, because their circumstances don't change. I don't doubt that there would be some change if they got really, actually close to someone they are normally bigoted against. I'm just saying it doesnt happen, and thats why they don't change.