When they are the butt of the joke, it is easy to extrapolate that the author doesnt respect trans people, it's that simple. Whether it's the "tricked you" deal, or saying "haha look how garish and obvious these guys in drag are", comedies run jokes through the whole chapterand that particular part of it is one. No one in this manga's world acts like being gay is no big deal or is there to make that clear to the audience. You're left with him being gay as the punchline. If you think crossdressing is funny, sorry that just isnt it. The author isnt going ha I'd love to put the world in drag so maybe they'd get a clue, the author uses a world in drag to laugh at the people that don't fit, don't "pass" and to mock men that are attracted to those that do.
My point on the tomboy things, is they are in a completely different universe than femboys, because of how gender works and how one is tied to a shit ton of transphobia and the other isn't.
Dude I am totally inclusive, but Japanese manga does not afford nuanced portrayal of trans and GNC cis people in any way, so what ideas do they intend to promote. Like just try and use your head to imagine what itd be like to be a trans woman in japan when all the old people hate you cause duh and all the young people hate you because the hoard of media presents you as this fetishistic fraudster. The
manga out there simply doesn't afford the nuance. It's well known Re:Zero's author is a transphobe and he pulled all the same shit with Ferris that has been the classic depiction of femboy.
These characters aren't real people, but the author's imagining of them so yes while its rude to assume and project the whole egg deal on real people, that's off the table when its fictional people and you're weighing whether the author is transphobic or relates to the character in some way regardless of their identity, theres speculaction Hemingway was trans based on correspondence and how he had his wife refer to him in the bedroom, he's long dead and lived in a time where trans people were not allowed to exist, so this speculation isnt directly harmful to anyone. Its all done in context and we ultimately afford his identity to how he's been largely referred to. When you look at the context here in manga it's hard not to see them as trans or relatable to the trans experience.