Why? I’ve yet to hear a single concrete reason as to why it’s better to substitute something else when we all know what we’re talking about. I––surprisingly, given my thoughts on humanity––tend to give people more credit than to expect them to be shattered by hearing a word even in an appropriate context, but okay with hearing something that refers to that word. Perhaps I shouldn’t though, maybe even that is an unreasonable expectation.
Literally the whole point is that it is a word that shouldn’t be said. This isn’t about people are saying “what up my ‘n-word,’” in that case I would agree. It’s not being used as the word itself, it’s being used when talking about it. There’s a distinction.