I guess clubs can let in whoever they want and turn away whoever they want ... it's petty and stupid, but I definitely wouldn't patronize any place that discriminated based on weight. I've seen some "chubbies" who are "hotties" at clubs who dance wayyy sexier than the skinny girls
So let 'em do what they do and don't worry too much about it.
Now if the state was making a law about it, that's weird and messed up. But private businesses can pretty much decide who their clientele will be. Of course, the reaction of the market in general will decide if the place stays in business or not. I think it's good to publicize these things but not to worry too much about them.