Every 15-20 years a new series of Euphemisms roll out as a purity test. It doesn't matter if they make less sense. Think about illegal immigrants (undocumented migrants), vagrants (unhoused people), and the mentally retarded (this one changes a lot I'm not sure what it is now.) Some people will be slow to pick them up, but that group gets smaller and smaller. The actual term gets more and more offensive. Eventually the resistant either give in or get fired once some HR complaint is filed about them saying negro one too many times. The younger generations are taught the new words in school and don't know anything else. Grandpa is just an old kook who says nigger because he's confused and they were less enlightened when he was young. It helps filter out young non-believers and can isolate the older ones from their family. You also get to sell new textbooks, medical books, and anything else with potentially offensive text printed on it.
