Actual racism is considered such a ghetto attitude that anyone using racist language earnestly so completely discredits themselves that the alleged "victim" can't take them seriously. As they say, "It's not what they call you, it's what you answer to."
It's probably a sign that we have less racial inequality when people can rib each other about nationalities or regionalisms the way we do about sports teams. As far as the Chinese comment from the OP, the perpetrator must have been some horking mainland peasant, since no respectable Chinese person would litter on someones motorcycle.