
can't sexuality be fluid though? i don't disagree with your other statements, and narratives that say "i'm not gay but..." are troubling, but sexuality is definitely something that can change over time (for some). it's not discovering what your "true" or "real" orientation is, it just can shift more to one side or the other. sexual fluidity does tend to be more common in biological women as well.
i just feel that the whole thing about liking someone because they're that person isn't such a bad thing to say :)

You are right regarding that sexuality can be fluid but thats really only true regarding those who like multiple genders. What makes it an issue is for those who are strictly homosexual and how this narrative can be used to say its a choice. When the LGBT community has been fighting so long about how they can't change how they were born it can actually harm the agenda which is why it bothers me so much. And on the other point I agree with its not wrong to like someone because they're who they are but for the most part this trope is used to condemn homosexuals. "I'm not gay but I like you" really undermines what its like to be LGBT and leans more fetishy to me. What they could've done instead that included a similar message is by stating how the character is either on the bi spectrum or how "out of everyone in the world i chose to be with you" signaling how they either already have that preference or how they came to know about there preference through that person. Again the work feels like I'm looking through rose colored glasses on the characters which when depicting someone who is LGBT and does have to struggle to find out who they are it can be troubling.

This manga isn't harmful for the LBGT movement.
I think all the points you made are relatively true. It would have been nice for the story to expand more on the main couple, their journey and their personalities in general. We know Makoto is kind, Yuuko is self-assured but that's about it. Also the "mean girl" Miki is very one-note and one of the most frustrating parts of the manga as you said. But saying it's "harmful" is way too much. Of anything, the takeaway message is something really important that I feel a lot of people reading understood: gender and sexuality isn't something that can just be assumed by appearance. And it's emotionally taxing having to constantly correct people and explaining why you are the way you are.
Some of what you said is up to interpretation: like saying Yuuko (the enby/agender character) is bad cause they get angry assuming everyone should understand their identity without an explanation. I didn't get this at all! I saw it as Yuuko picking up on people making fun of them and their partner, as the people ignored Makoto's charitability just to be ignorant.
You literally have two sides of the coin with Makoto and Yuuko. Makoto is more patient and willing to go through the emotional labour of appeasing others. Meanwhile, Yuuko states their identity at the start and expects to be respected for who they are without needing to give an explanation and isn't bothered to deal with Miki who has malicious intent in her interest. That's why it's so satisfying when they put her in her place in an albeit unrealistic way where Miki immediately starts crying and shows her jealousy. Not the best writing ever but ain't no way "harmful" yk?
The "inconsistent identities" point is interesting. I feel like that's a much bigger topic than just a problem with this manga. Cause the line between understanding that sexuality and gender isn't something you choose BUT can also develop and change as you learn more about yourself is often badly portrayed. You mentioned this with the whole "I'm not gay but I like you" trope. In an isolated analysis, the couple not caring about each other's genders or labelling themselves could be seen as this trope. But they both identify as fem-presenting non-binary people and just happen to like each other. They don't scorn at the idea of being perceived as gay and even try to explain the difference between attraction and identity. In some manga, you can immediately tell when it's by a cishet who wanted to write something interesting versus someone who actually wanted to explore these themes with respect. From the main message alone, I feel pretty confident that it's the latter - but I guess idk the author like that lol.
(Plus there's nothing wrong with not wanting to label your sexuality. And different trans people experience dysphoria differently & you can't dismiss one over the other (e.g. social dysphoria vs physical). The idea of "your dysphoria needs to be believable or you're not really trans" is harmful as well lol. Still those are WAY bigger topics outside of the realm of "a manga written in fictional universe" so I won't go into them)
Lastly, a big issue with your take is that it ignores the fact that this is a one-shot manga! A short story. Literally one chapter that aims to introduce characters to empathise with and convey a message to the readers. All the other manga you linked (which I highly recommend too) have multiple chapters and an overall story arc that can be expanded on. In fact, I think that for such a short read, it's impressive that the story manages to cover a lot of specific issues, such as conforming to "easier to understand" expectations of your identity and how that can hurt (e.g. the school teacher telling Makoto to say he has an illness and wants to be a girl rather than explain being bigender, very similar to how bi/pan people are told to just say they are gay or straight depending on who they are with)
TLDR:
It's been a few years so maybe your opinion has changed lol but I thought it was weird how the top comments were angry at the horrible representation. At the end of the day, it's all opinion and interpretation but... like... is it perfect? Not at all, no. I wish there was more about their realisation of being genderqueer and the mean girl wasn't so stereotypical. But it definitely isn't "harmful", I have read FAR worse! To ppl who actually are non-gender conforming or are enby and don't dress androgynously, it's a very straightforward portrayal of what they go through. So if you read it and you are angry: fine. But if you read it and you loved it and felt seen, I hope this WAY too long response reaffirms your feelings :3
(still go read the other linked manga though, they are more engaging reads.)
Its been a over a year since I've read this manga and now I got a lot of comments under the post I made. Some of my opinions have changed while others stand strong so I figured I'd make a new post talking about why I think this manga is bad representation and how it harms the LGBT movement.
First let's talk plot.
One of the things that rubbed me the wrong way that I couldn't articulate in my earlier comment was this "fairytale" characterization of the cast. The antagonist was very one dimensionally manipulative and how in the end she ended up being jealous of their relationship came off more like a "and we all clapped" at the end when our main couple left her crying only to go home and have intercourse. The villain was flat and the protagonist couple felt the same way.
The nonbinary character was easily the worst in the whole manga. They had no character other than getting mad at others for misgendering/mistaking their sexual orientation. The expectation for someone to a automatically know your gender can only lead to upset feelings and set up false expectations for the young audience who will read this. Overall the character was just bland and a cardboard cut out that could be replaced with any other character.
Now let's talk about the dysphoria issue
What I wasn't able to put into words in my review when I first read this was why the dysphoria in the manga didn't work and I need to touch on that. Makoto our main character was born male and was described as wanting to present female. However they didn't feel any sort of discomfort with their male body. The problem is with this type of description the interpretation of their identity could fall a multitude of ways. Makoto could easily be described as a cross dresser, mtf trans, or what was depicted in the manga bigender/gender fluid. Another think to note on going through and re-reading it a couple of times their use of pronouns for the character where either never depicted or used as he/him (even by the nonbinary character). And the idea of how their partner had all the answers on Makoto's gender depicted their emotions as simple and a "duh" moment like it is so obvious what they are when in reality finding your identity can be uncomfortable and complicated. People often go through many different labels before landing on the one that fits them best and to make it seem so simple doesn't show how difficult it can be.
The other issues
No we are not done. Upon rereading the manga i hate how they describe sexuality and say "I love xxx because they are xxx not because of their gender" and how thats how our couple describes their sexuallity throughout the entire manga. Sexuality is not something that can be changed and you are born liking whatever gender(s) no matter your gender identity so the way they describe it is equivalent to the way you see homosexual couples in yaoi as well. The narrative of "oh I'm not gay I just like xxx for xxx" is such a cop out and could've made the narrative for the story so much better.
Also the name of the manga being my girlfriend is a crossdresser doesnt help with representation.
In conclusion
Overall the manga has flat characters, inconsistent identities, and a romanticized view on gender and sexuality. If we want good representation in our media we shouldn't be afraid to call out the bad or mediocre. This manga is by no means the worst, however their is nothing exceptional or narratively interesting about it besides the notion that it talks about gender and sexuality. It was a 4/10 at best. All right ive talked enough
If you guys want better examples and representation imma leave a list.
http://www.mangago.zone/read-manga/yuureitou/
http://www.mangago.zone/read-manga/umareru_seibetsu_wo_machigaeta/
http://www.mangago.zone/read-manga/bokura_no_hentai/
http://www.mangago.zone/read-manga/shimanami_tasogare/
http://www.mangago.zone/read-manga/hourou_musuko/
http://www.mangago.zone/read-manga/is_otoko_demo_onna_demo_nai_sei/