"Certain activities do require a certain dress code" - and who dictates that, Johnny? The law? The clubs? You? Thing is, your gym isn't every gym, and what suits one may not suit another. Neither can we expect others to dress according to our personal tastes and dress codes, especially where a strong corporate one does not exist. I happen to find the sight of fat-bellied males in skin-tight swimwear quite repulsive, but that gives me no right to ask the pool management not to allow it.
You'd probably expect a golf club not to allow males to play topless, but again, that's a golf course and not a sports hall. In this case, there's nothing in the dress code about it, and I for one wouldn't object (and it would appear I'm not the only one).
As you say, if you don't like a place's dress code, you don't go there. That goes two ways. If you really can't face the thought of looking at a naked male chest, then you don't have to join.
You say "get on with the game and worry about more important things" - absolutely great piece of advice, Johnny. Well worth taking - worry about the game and not about what someone else is or is not wearing. Sounds like DarkMajes' playing colleagues are doing just that - unlike her ladyship.