'Bad' in what way? I go clubbing to have a good time, not stand there holding up score cards to show how good or otherwise I think everyone else's dancing is.
Sure, clubs where people mince around a pile of handbags getting bladdered on Bacardi Breezers are shit, and granted there are plenty of them Britain, but they're not the kind of clubs I go to. Clubs where people are dancing without regard to what they look like and just enjoying themselves, is more my thing.
I suspect clubs where people do 'good' or 'proper' dancing may be full of people just showing off, concentrating more on what they look like to other people rather than simply having fun.
In my experience, most people can dance reasonably well if they're suitably relaxed and uninhibited, and in any case, I'd rather see amateurish enthusiasm than professional exhibitionism.