I picked a project at random -- the Tarantino one, which lists every death or curse word in every Tarantino movie -- and browsed through the data:

https://github.com/fivethirtyeight/data/blob/master/tarantin...

I found it interesting that the author was willing to catalog each curse word by writing it in its entirety -- except one, the n-word (which, by the way, appears 179 times in Tarantino's movies, with the bulk in "Django Unchained" and "Jackie Brown"). The article for which this data set was compiled similarly censors none but the n-word:

http://fivethirtyeight.com/features/complete-catalog-curses-...

I happen to think that no one of any ethnic group should use the n-word, and I do not use it myself, but I think in the context of cataloging curse words, where you're writing at a sort of meta level (i.e. writing about words, rather than invoking them yourself) it's just as acceptable as in the other cases to write the word out. But the fact that the author made this one exception reveals a bit about how he sees the word in relation to the others.

For instance, you might argue that the varied versions of the f-word might be strong language, but in a different category than the n-word because the latter is an ethnic slur.

But the author has chosen to write out other ethnic slurs in their entirety (e.g. the w-word, referring to Mexicans, and the j-word, referring to Japanese people, and the g-word, related to Asians), and also slurs related to other groups (e.g. the f-word, referring to gay people).

So, even if you're talking about just the set of curse words that insult a particular group of people, the author has set the n-word apart.