I don't deny that almost anyone can potentially be a racist, because this is about deciding who the friends and who the enemies are. I bet most of the racists would stop being racists if they thought that those races were "friends". I think racists are just more sensitive to knowing who the friends and the enemies are. And they can't use their rationality to conclude that it's erroneous to attribute certain characteristics to an entire race.
But if they're supremacists, then that's a different matter and their idea on superiority needs to be attacked.