To be honest, I think there are significant differences between the two terms - "coconut", I concede does very definitely does go along with a discourse that prescribes what it is (or should be) to be a black person. I also thinks it inherently sets up different values for different races. And I'll admit that I'd be uncomfortable on a plain human level hearing a black person use that term, let alone a white person. But I think the term "chalky" is different - it was coined (or at least given popular currency) by a racist as cover for his racism. To use that term specifically to refer to someone who allowed themselves to be used in that way is, I think, entirely legitimate. I don't see why it would be racist used in that way - perhaps you can explain it to me?