It's not about being the best dancers, or putting on the best show.  For that, go watch "Dancing With the Stars" or better yet a performance by your local ballet troupe   It's about a community getting together to enjoy each others company.  Dancing happens along the way.  Tolerance should happen, too.
Even then the response should not be to ban the offender.  Just to educate them firmly and stop the problem behavior.    Of course if the problem doesn't stop further action may be necessary, but still it is unlikely to require a ban.
The most serious case is a "predatory" dancer who takes advantage of other's weaknesses.  A dancer who sees the occasion as a meat market or an opportunity to "get a little."  A dancer who uses the occasion to intimidate or harrass other dancers.  For those cases, a ban may be the appropriate response.  Fortunately these cases seem to be rare.

Dale

--
There are only two hard things in computer science: cache invalidation, naming things, and off-by-one errors.