People who are the subject of the word get to say what they will accept.
Being corrected by those who aren't members of the group described is obnoxious, I agree.
Besides that, the new, more sensitive word becomes a pejorative in short order. E.g, "sped" for "special education student".
The people who use the words that others find unacceptable will be judged by everyone who hears them speak, and mostly silently.
Everyone who hears someone use the word "nigger" will define that person at least partially by what they have heard. Other words too.