Dare To Ask Talk And News About Our Differences 
I can dance! I know loads of white people who can, and also a few black people who can't. Maybe white people are a bit less self-conscious, or they just get drunker quicker, and therefore they might get up and dance even if they know they are no good. It's kind of acceptable among my white friends to be rubbish at dancing, as long as you're feeling it. Maybe black people worry that because of the whole black=natural rhythm thing that they'll be seen as comedic if they really can't dance, so they don't bother. I seem to remember a black British comedian doing a sketch on this a while ago.
Everybody should get dancing whether they're good or not, and people should be less judgmental of others' abilities. All that matters is you get your own thrill out of it.