The difference between "fuck" or "bitch" and "nigga" (and all the other racial slurs) is the presence of discrimination.
While "fuck you" can be said to anyone, racial slurs were conceived to be offensive to a specific group, the same goes for homophobic terms. We don't get complaints about someone expressing their anger at something by saying "fuck this shit" but we do get complaints about racially offensive words. It all comes down to what's socially acceptable to north american culture. While you might use that word with your friends and no ones offended, if you went a bit further north and walked into a bar and said "what's up my niggas" to a bunch of black guys, with all the friendliest intentions in the world, you might not walk out in one piece.
But wasn't bitch once for women only?
It no longer means that, just like "Nigga =/= ******"
Doesn't mean much, i can say americunts and offend an entire nation. And look, not censored
I'm not sure why, but I laughed so hard just now
I could walk up to a group of (urban) black guys and say
"What's up niggas?"
and they'd be like
"Sup baby gurl?"
Now if I said
"Sup ******s"
I'd probably get the piss beaten out of me