The New York Times has published a thoughtful essay about the N-word, by an etymologist, and if you have access to their Opinion pages I strongly encourage you to go read it.
In 1934, Allen Walker Read, an etymologist and lexicographer, laid out the history of the word that, then, had “the deepest stigma of any in the language.” In the entire article, in line with the strength of the taboo he was referring to, he never actually wrote the word itself. The obscenity to which he referred, “fuck,” though not used in polite company (or, typically, in this newspaper), is no longer verboten. These days, there are two other words that an American writer would treat as Mr. Read did. One is “cunt,” and the other is “nigger.” The latter, though, has become more than a slur. It has become taboo.
Without belaboring the subject, I’ll add just this: I can remember when some of the ethnic descriptors (Dago? Polack?) that nobody would use nowadays were in common usage, and they were often — not always, certainly, but often — used as judgment-free nouns, no malice intended; culture and education are implicated in language usage. The Times explains their decision to publish the article, here.
Language is much richer and complex than the simplistic rules observed by the (usually) hypersensitive language police.