For reference, I'm old enough to have been a child in the casually, obliviously racist period in the United States -- many terms that are now considered "racist slurs" were in common usage, among otherwise decent adults as well as children, and to people of my generation they mean certain things that are largely independent of their racist label. While I agree that we should no longer use these terms without thought, I believe there are situations in which one of them gets the thought across more effectively and with far fewer words than beating around the bush.
For instance, in a recent question (now deleted, because it was apparently more of a Worldbuilding.SE question than about role playing), I said that my town has, among other threats that aren't there, no "injuns" -- with the term in quotes, just as here. The post was edited almost before I'd finished rechecking for typos, to "remove racist slur".
Now, to me, use of that term, in quotes as I did, is a case of referencing a specific past usage: the 1950s-1960s TV Western usage, as in "The only good injun is a dead injun." There was no indication in the question of an actual culture; what I was trying to say was that there is no culture subject to that sort of prejudice -- without writing an entire paragraph to do so.
This is in part a linquistic distinction: I haven't referred to Native Americans as "Indians" in decades, nor used the term "injuns" to reference a race in somewhat longer. None the less, I wouldn't go so far as to change Tom Sawyer by editing the character name of Injun Joe -- and it doesn't seem quite right to call referencing such a cultural artifact a "racist slur."
So, the question is, how should I go about including an old meaning, without having the entire idea deleted and potentially getting Code of Conduct strikes?