It's been wild seeing all the people immediately jump to calling this transphobia. I am literally asking for people to respect other peoples' gender identities.
I even very specifically did not say "trans people" in my original post, because the problem is not and never was trans people. (In fact, I'd say a GNC safe space needs to let trans people in for the same reason any queer safe space, including GNC ones needs to be able to let cishet people in--if it's not a safe space to people who are questioning, it's not a safe space)
I wouldn't even go as far as attributing this behavior to trans people. When it comes down to it, the people themselves are not the problem, it's their behavior.
The problem isn't trans people, it's people--of any identity--who think that, for some reason, the phrase "you should respect other people's identities" does not apply to them.
Call it queer infighting, but I feel like a safe space for GNC people should not have people who insist that being GNC is a pipeline to being trans.