This whole thread is clearly meant to be ironic, for anyone taking it seriously.
I think most people on this site who use the word "nigger" and similar racial terminology do so because it sounds edgy, and this is one of the few corners of the internet that won't ban you for it. Also, I wouldn't be surprised if this site were used mostly by people in the United States, and the pearl-clutching over the most trivial things over there seems to be quite insane. So it makes sense that some people would release all the pent-up pressure here, where there's no suppression of speech (as far as I'm aware).
I don't think most people here are actual racists. And if they are, well, too bad. I don't personally think any particular race is superior over the others, but if others do... well, they're entitled to their silly ideas.