I recognize this isn't a Mogstation outfit, but to illustrate the difference...
Think back to Copied Factory, where guys got awesome 9S-themed longcoats with double-buttoned fronts and all, while women equipping the same gear for some jobs got what I would politely refer to as 'NieR cosplay lingerie'. And while I have nothing against the aesthetic, it's not the aesthetic I have for my character; I wanted the jackets.
(Needless to say, Puppets' Bunker made me very happy. Thank you, sweet Type-53 fending coat; you are my new favorite GNB glamour.)
So let's say the next alliance raid were to have the women get badass longcoats and pants, and the men got skimpy chest-bearing tunics and shorts that basically look like a thong; a modern alliance raid version of the Coliseum subligar. In effect, a flip of Copied Factory.
If through some bizarre twist of fate that were to happen, you won't have any reason to complain, right?
After all, the only people who would benefit from a change there would be women who want to be able to wear both outfits, and "males players who want manly stuff". But the "females characters" who don't want another set that is basically underwear/lacking pants (see my forum signature) and (to use your term) "femboys" would be happy.
They'd gain nothing from a change there so, as you point out, why should they have to share? Obviously it should stay gender-locked, yes?
If you would be happy in that scenario and not want the badass longcoats unlocked for guys too, then awesome, I respect you for sticking by your position even if I disagree with it.
But if, in that scenario, you would want male characters able to wear the badass jackets and pants as well, because you didn't want the 'cosplay lingerie' set yourself... then you may want to examine your position a little more closely, since it seems a bit hypocritical.
Because if "I don't think people should have to share" only applies when you have what you want and would have to share, but not when you want the thing that someone else has... then your opinion seems less "I don't think people should have to share" and much more "I don't think I should have to share with girls."
And in my hypothetical above example, why should I -- who don't tend to wear girly outfits on my character -- want to share my badass jacket with you? Sure, you get what you want. But if I don't want to wear the skimpy thong, what do I get from the gear appearances being unlocked, gender-wise? By your logic, in that scenario, you should stick with the thong.
After all, you wouldn't want to be unfair and make people have to share the outfit but get nothing that interests them in return. Right?
That said, I don't think everything needs to be gender-unlocked, especially because going back to do that on all previous outfits would be a pain, and also because the game is not set up well to let you pick which of a male/female differentiated outfit's appearance you wear. (e.g., Copied Factory gear and such.)
But I do think it'd be nice if there were more options going forward, especially since I'm very, very tired of healer gear turning into a bathrobe and underwear most times when women wear it. And I do think that outfits you pay actual real money for probably could stand to be gender-unlocked; there's definitely a few sets I'd really like to have pieces of that are male-specific!
(Mind you, I actually do think more racial locked gear could be neat, as much as the hempen set annoys me. I think that would provide an interesting avenue to delve deeper into the various racial cultures... and frankly, I love lore, so I'll take any excuse to get more of it. So something that's part of a ceremony specific to, say, Seeker of the Sun miqo'te and thus only equippable by Seekers? Yeah, I'd actually find that interesting.)