I'm a Black Canadian male and have been teaching in China for nearly 6 years. I have never experienced any of the racial discrimination that we, as Blacks, commonly face in North America. If a Chinese person does not like you, it's usually because you are not Chinese.
I believe that giving respect gets respect. This attitude has always worked for me. Like every place else, you have the good, the bad and the ugly. A qualified teacher, black or white, makes you one of the good guys (or girls).
Any problems, and there have been a few, came from the white folk who brought their garbage with them. But resolution of these situations, North American style, makes for an interesting culture lesson for the Chinese. Unlike white folk, Chinese are quick learners in this area. The 'n' word disappears from the vocab and they will NEVER insult your mama.