Venues (EG Nightclubs) are always concerned over the mix. They like to keep the percentage of women high. hence a tendency to discourage large all male groups,
Same goes for race too. Every now and again you hear stories about how Black people feel they have been excluded from a venue for being Black.
While I can see how people might feel hard done by over this, I can also see the venues POV too.
Get too many men in your club and eventually you will sacre away the girls and before you know where you are you will either go out of business or become a gay bar. Now Gay bars are fine, but a club owner has the right to run his or her club the way he or she wants to and if they do not want to run a gay bar, then they should have the right not to do so.
Similarly, a handful of Black customers in an otherwise mainstream white dominated nightclub gives a nice cosmopolitan feel to the place.
But get too many and the White people will start going elsewhere and before you know where you are you will be running a hip-hop club. Again, hip-hop is fine, but also again, An owner shouldn't be forced to become one if he doesn't want it to be.