This is great, they think it is a 4d chess(*) move they pull on people. They think it both outs people who take offense and preselects your friend group for people you can convert into neo-nazism. And anybody who takes offense gets to look like a crazy person and leaves.

What actually happens is that people don't always react to your slurs directly but certainly talk among each other, this will close doors for you and cause people to deprioritize you as a friend. You will just get invited less and 'forgotten' by people (unless they suffer from the geek social fallacies, but geeks do talk to each other about those), you will get the reputation as the n-word guy, and people will warn others about you, like you are a broken stair. It also creates a culture of shittesting your friends and regularly testing your friends to see if they match up with your ideals or are 'good friends' is a very toxic way to instill paranoia in yourself and reduce the amount of friendships and professional opportunities you have. So I'd suggest he carries on with it, ow sorry 'his friend'.

*: it is 4d chess, in a sense that he made up his own rules, they are way more complicated than needed, don't actually add anything compared to normal 2d/3d chess, and by playing a different game than the rest of the world you are actually just making illegal moves which ensure people will not play with you anymore. Confusing a social game for an intellectual game.

E: forgot to ask, who is this dweeb again? Answered my own question: Ow wait it is Putanumonit