I don’t know if this would help or not, but I’ve found that pretending not to know what people are talking about when they say stupid things is a wonderful way to keep them from saying something stupid, because then they have to explain themselves. In plain words. People like that rely on your intelligence to get their point across, even while they insult it. It takes some practice, but if you can train yourself to smile innocently and say “whatever do you mean” whenever you choose to, it’s another weapon in your arsenal.