What if a black person says "To all my n*ggers out there, x,y,z" on twitter, vs. a white person saying the same thing. Will the white person's tweet be removed, or both?
More substantive comment: why do we care about a person's race or gender when they use particular words?
I'll not go into that concept further for fear of igniting another tired flame war.
Sure it's complex, convoluted, and controversial.. but as long as we put the right people in charge to make the decisions for us, it will all work out fairly.
Similarly, if a white person publicly says something discriminatory against black people, it's a much different context than if a black person says the same thing. As an simple example, imagine a two black people in a room of 40 white nationalists: If one black person says to another, "hey n-!", that's much different for the person hearing it than if one of the white nationalists says the same thing.
There's a lot more to that word, including black people taking power for themselves and away from racists by using it (really a brilliant, innovative way to push back), but that's too much to write here and now.