You just pointed out that gaming communities are myogynistic and transphobic hence disencouraging these people from picking up the game and grinding. The point of GC is to provide friendly conditions for them to assimilate into the "regular community", not because women and queer people's brain are tinier than males. There are not such thing as "competitive advantages".
It's literally better to play in T2 than play in GC with less salary.
Dudes easily finding dude gamers to create premier teams with, T1, challengers having better coaches, scrimming good teams more often, bunch of dudes reportedly not wanting to play with girls,... are the "competitive advantages" . If these supposedly existing faking people you're talking about can't even qualify for T2, you would only assume they would be able to "farm" Vania Mimi Mel who have a "more fair condition to grow" if you think females are intellectually inferior.
Riot is already planning a GC with mixed genders.