By your understanding, Peeping Tom can't peep on Dick and Harry. That makes no sense.
I'm not sure I understand your point but I will try to address it anyway. The classic peeping tom is a guy peeping into a window at a girl. He is likely trespassing on her property and is definitely invading her privacy by peeping into an area (her home) where she has an expectation of privacy and where he is not allowed or invited. That classic scenario could also play out with a guy peeping at another guy or a girl peeping at another girl. Still illegal.
My point was that if a guy (ostensibly, but not really, trans) is legally present in a locker room, how can that be a peeping situation? Everyone is there legally (invited) and there is no expectation of privacy. Of course the scenario changes if someone is behind a curtain or something and someone else is peering into an area like that where there IS an expectation of privacy.
I will acknowledge that the prurient interest concerns around an ostensibly trans man (presumably not really trans) leering at women in a changing room kind of break down when you acknowledge that homosexual men or women have always been sharing locker rooms with people of the same sex - to whom they are sexually attracted. I am not sure what to do with that fact.