Double standards much? I know there's no real set deragatory term for white people, but whites these days are now expected to keep their traps shut and take whatever abuse any other race wants to give. On the other hand, I hear some black people constantly referring to each other as "n"-words. But these days I bet if you went to NYC or Chicago and said "black", regardless of context, you might get shot if you're white, and then if you live the shooter will go and sue you for racial slurring, and probably win the suit.
The scenario was hypothetical, but the double standard illustrated in it. "Post-racial America"? BS if you ask me, it's just that the roles have been switched, and either way is no good.