I mean, that term is too loaded. It's either Bad (if you're republican) or Good (if you're not). Obv I think Good is closer to the truth, but it's more complicated.
Bad 1: using racial slurs (obv)
Bad 2: using insensitive words like "illegals" or "retarded" that we haven't yet elevated to the level of Really Bad Word, or other sort of language that indicates racist thoughts
Bad 3: "postman" instead of "postal worker" or other sort of uninclusive language
But like, these are different levels of badness. I feel like if your uncle starts dropping n-bombs, you should be like "dude. don't say that." But if he does a thing that is Bad 2 or Bad 3, don't jump all over him. Use the right word, and if he asks you about it, explain why in as non-confrontational and non-superior a way as possible.
If people have deep-seated racist/sexist/*ist beliefs, you're not going to change their mind by saying "that one word is bad" - they're likely to think you're just being "politically correct." And the cartoonish stereotype of PC is of course silly. Even though the sentiments behind PC are totally correct and most people who "hate political correctness" really mean "Can't things just be simple like they used to be back in the good old days?" without realizing that the good old days weren't so good for everyone.