Call them cowards; the accusation that stings as much as "racist!"

The best insults are both true and highlight a character flaw to everyone including the recipient. They are really great if they cause introspection. 

Tolerance and equality are the highest virtues of cowards just like courage and truth are the highest virtues of the racist. Aristotle said that virtue was found in moderation but I think that people only have vices, and virtue is the lie they tell themselves and others to cover the turd in perfume. There's no moderation because the extremes are just two craven impulses masquerading as virtues. There's really only the craven impulse underneath it all. Are you a cowardly weasel or a bigot with the will to dominate? Your "virtue"  will be tolerance if the first one and courage if the second one, assuming you have either. 

The mirror image of calling someone a racist is calling them a coward and culturally it is just as powerful as an accusation. It is powerful because it is true. It is powerful because it induces self-reflection in the target. It is powerful because every time somebody quibbles or refuses to understand things like mass replacement it's because they are coward. When they inevitably call you a racist tell them they are a coward. It works, and it's embarrassing, and it's true.