That's one of the dodges we see around here all the time. There are all sorts of variations on it, but basically it's saying that there's no problem with the transwoman in the female changing room as long as there is not lewd behavior.
That's not a position that we accept. The problem is that a male is present in the changing room. It really doesn't matter what he is doing, or what pronouns he is using. If the person is a male, and the person is in a changing room for ... uhh....(oh look, jerks have changed language so much that no matter what I write some moron will say but..... I'm just going to say "women". Anyone who pretends not to know what I mean is lying.) and the person is in a changing room for women, that's unacceptable.
And if you could convince me that most women don't feel that way, I would change my mind. My interest is protecting the interests of women. You know, ordinary women. Regular women. Cis women. Female women. Those sorts of women. If I ever come to believe that, really, they don't mind and would prefer to share the locker room with transwomen, then that's cool by me. Until then, I will support them in their desire to remove all penis equipped people from their private spaces.