There are so many discussions about his gender despite the work constantly reaffirming that Mei is a boy in mind and body.
His gender is important to the narrative and essence of the character, he wouldn't be so charming if he was a girl just claiming to be a boy.
Movements such as the Hawkeye Initiative did not understand what fanservice as a concept is. What was intended as a way to show the ridiculousness of female fanservice, only came to dismiss and ridicule the idea that male characters can be sensualized and sexualized in the same ways as their female counterparts.
What its proponents couldn't understand is that those female depictions were intended as attractive, their mockery was unable to grasp the true meaning of those images and what they were meant to evoke on viewers.
Because people refused to understand and relate to the sexual desires present in female fanservice, assuming that all of it was nothing more than objectification and contempt towards women, they now struggle to comprehend that the male form can be portrayed in an erotic manner and that the male body can be appreciated for traits and qualities that are unrelated to a caricatured perception of hypermasculinity
Many make the mistake of perceiving Power Fantasies, which can be sexual however are not equivalent to female fanservice, with male fanservice. As an example see the discussions surrounding Captain America's beach skin on the game Marvel Rivals. The character was not made to be ogled, desired as a sexual partner or a target of lust, they exist as a caricature of a powerful male in exhibitionist attire. The focus is on the big penis and large muscles Steve has, his overwhelming masculine prowess, his power, and how ridiculous it's for a man to show so much skin. You're supposed to find it funny that his dick is bulging out of his thong. Yet, because people have no proper framework, they see that Skin as being equivalent to that of the female characters and think that this is male sexualization.
The Hawkeye Initiative should have taken some notes from Japanese art and portrayed make characters as attractive when put in conventionally feminine poses and attires. This would have been more revolutionary and elucidating.
Games such as Twisted Wonderland, Enstars and Touken Ranbu, constantly expose their male characters in the same way one would expect a female character to be exposed in a fanservice heavy game oriented towards men, However, because the artists behind those projects have a genuine appreciation for the male form, what they present to the audience is not mockery but sincere admiration for masculine beauty and sex appeal.
Touken Ranbu for example has a mechanic where characters lose pieces of clothing when damaged by enemies, a concept reminiscent of female fanservice found in male oriented games. The higher the damage the higher the exposition, the characters never come to look funny in that situation, they always look erotic. Their exasperated faces, their costumes yielding only where is of interest for the viewer, their effort to cover up or to ignore the exposition, all of it is done to arouse the audience, it's genuine male fan service, without second intentions or dismissal.
One could even mention how Shonen series market their male characters. The sexy crossdressing found in stories such as Iruma-kun and Baka to Test, and the marketing campaigns that revolve around dooling and exposing the body of themale cast, as it's done with Wind Breaker and Tougen Anki, are far better examples of how male characters can be sexualized in ways comparable to female character than merely making Hawkeye look weird.
In my view the hate some have for sexuality as a concept and form of artistic expressions clouds their views and prevents from understanding the intentions of artists and the complexities of sexual art. And because their thinking is simplistic, they're prone to falling into ideological traps, such as treating female modesty and chastity as moral imperatives while reducing male beauty to how effectively a man performs within a conservative framework of masculinity.
On one hand you have people who believe that the ones at the top should be those who were born with the qualifications to access that space, ex: A top athlete needs to be a genetic wonder, because otherwise it wouldn't be fair that they wins so much and are so above everyone else in that sport.
On the other you have people who want the top spots to be given to those who are dedicated and made more effort than everyone else. Ex: The winner of a competition should be the one who spent the most time preparing for it, otherwise they didn't earn their victory and are taking it from the hands of those who deserve it more.
In the end, I believe both sides have valid arguments, but neither is correct, because the very premise of this discussion is wrong. Neither talent nor hard work nor even a combination of both can guarantee success. To reach the top one needs to take into account a lot of external factors, many of which they cannot control and have nothing to do with their capabilities.
I believe many times people misunderstand the optimistic, inspiring and very contextual speeches and themes of Shonen as ideological arguments meant to go against the "Hard Truths" they believe in.
When series like Dragon Ball,Naruto or Black Clover talks about "hard work beating talent" what they mean isn't that talent is irrelevant or that the gifted will always be defeated by someone making more effort than them (See that in all of those stories we have talented characters winning against those without talent or achieving huge feats without much effort and being complimented and adored for it), what the story is trying to say is that you should make an effort to try and improve yourself even when the odds are against you, that the conditions of one's birth shouldn't define their life or role in society, that even someone who's considered useless or inadequate can achieve great things if they work for it.
Many also ignore the narrative context in which those themes and speeches exist. They're not meant to put those who are gifted down or to invalidate the idea of talent, but to tell the audience and other characters, usually antagonists, that you can achieve big things even if you're of lower status or face disadvantages in life.
There's also the opposite side of the coin, where people pick stories where cynical speeches are made and interpret it as the author trying to tell the audience to give up or accept the "harsh truth". A recent Shonen example of that is Jujutsu Kaisen, where the character's skills are directly linked to their talent and no amount of effort can allow you to improve, something that exists in the world to be challenged by the characters. Even if they can't reach the top, even if their actions and lives have no proper meaning or value in the eyes of the universe, they still have worth and should be preserved. Even if Sukuna is better than everyone at Jujutsu that does not mean his life and wants hold more worth than that of the weak or that the ones below can't come to reach him through other means.
I think turning those talks about nothing, but the validation of one's personal social hierarchy, takes away the depth and complexity of the themes being explored by those narratives.