There are women who actually want to attend the LAN party (as evidenced by the fact that they used to be allowed, were present, and "caused problems"). Are there really men who really want to get into Curves? If that demographic exists, then sure: open the gyms!
But honestly, it seems like you're just nitpicking here because you don't want chicks at your LAN party. Some of us find that pretty hateful.
Nah, I'm nitpicking because I truly believe in equality. What's sauce for the goose is sauce for the gander.
If a "women's" gym is the closest to his house and has the equipment he uses (e.g. I didn't know treadmills were gender-specific) then why shouldn't a man go? His money's the same as anyone else's.
The women's gym only exists because the atmosphere at the "open" gym is misogynistic. It's just a workaround. The real solution is to make the "open" gym friendlier. Then having a men-only or women-only gym would be stranger.
But honestly, it seems like you're just nitpicking here because you don't want chicks at your LAN party. Some of us find that pretty hateful.