@ Wiwaxia Their take wasnt transphonic at ALL. They were NOT saying she was fooling gyaru-chan by dressing the way she does or looking fairly masculine- that has zero baring.
The issue they were raising is AFTER gyaur makes this mistake- (to nobodies fault) - she should then have let her know she isnt a boy like she thinks. I also agree that its not gone on long enough yet to matter. They have barely interacted since then- but she does need to explain it soon.
You also cant compare it to a closet trans- because she is NOT. She has no particular reason to hide her gender at all beyond a bit of embaressment about being seen as lame or something.
No, "you need to explain your real gender to someone who made a mistaken assumption and if you don't it's deception" is still a transphobic take.
The issue is the narrative about "gender deception", which is fundamentally transphobic whether or not any given fictional or real person has a "reason" to hide their gender. (As if fear of homophobia wouldn't be reason enough! Even in this scenario where the mc isn't trans, the stakes are still potentially much higher than "being seen as lame". Come on.)
Could you elaborate on how it's "fundamentally" transphobic? I can understand how it could very easily slip into that sort of territory, but there does seem to be a distinction between lying about your sex/gender and not providing info that you're not obliged to provide, such as what genitals you have.
I think it'll be easier to understand with some analogies.
"How could you not tell me you were a girl?"
"How could you not tell me you were black?"
"How could you not tell me you were Chinese?"
"How could you not tell me you were Muslim?"
Etc.
There is a presumption here that keeping that information from other people is a form of deception. And the corresponding implication that to keep that from someone is a form of violence, which would then necessitate a violent response. The answer is that it's no one's business.
Of course, you could argue that there are certain things that you should reveal in a relationship. If you have religious differences on how you should raise your kids, then the topic of your respective views on faith definitely needs to be above board. And yes, when physical intimacy comes into play then discussions of how you go about that should also be above board.
But that doesn't hold true for 99% of interactions. Your coworkers, your customers, your classmates, and any other strangers in your life have no right to know that information about you. Acting like this is a deception when they aren't dating is to presume ownership of that aspect of another person's privacy. Just as it would be xenophobic to demand to know where someone was born before interacting with them, and racist to demand to know the color of their skin, it would be sexist/transphobic to demand the same for their gender.
At least, this is my best guess from what @Wiwaxia was saying. Please correct me if I am wrong.