This is probably the first mmorpg where you see players complaining, because alot of mmorpg give the players the option to wear female outfits. World of Warcraft a 2004 mmorpg, has no male/female slot, all the outfits is for everyone, so males can wear female outfits. The same can be said for majority of F2P mmorpgs. Elder Scrolls Online has no genderlock aswell, I have often seen male wear dresses, because they can, heck even Blade and Soul which was released in the west this year gives males the option to wear sexy female outfits.
So I would not be suprised if people were not complaining on other mmorpgs, because why complain, if you already have the option to crossdress?