A lot of people struggle with what to say when someone in their company says some fucked up *-ist bullshit. They want to say something in a way that makes it clear that what that person said was wrong and why.
You want to be respectful. You want to sound erudite and educated. You don't want to hurt their feelings. (Despite the fact that they already hurt you by saying fucked up bullshit). But really, sometimes that just doesn't work. So, to give you a model to work from, I offer you this: