I remember reading that when people have racist reactions like what you’re describing it’s like a different part of their brain triggers and then their frontal lobe (for higher logic) sort of suppresses it. I really wish I could remember more about this but I definitely remember learning about this in psychology. Something like when a baby sees someone of a skin color they haven’t seen before they get nervous, but when they’re older different parts shut it down. The memory is very fuzzy.