I think this is part of where the masculinity/maturity conflating comes from. If the masculine ideal contains notions of leadership and assertiveness, which I suspect it does for most, then feminity in contrast contains ideals of submissiveness and deference.
I also suspect most notions of maturity run counter to those "feminine" traits so the double negation connects maturity to masculinity, which is where someone might feel the need to fight back against that notion. There are a lot of assumptions underpinning this so I am very open to being wrong.
I guess I just reject the idea entirely that 'masculinity' and 'feminity' must be composed of mutually exclusive traits. in fact that seems very binary and toxic to me, defining masculinity as inherently anti-feminine. I think they can and probably should have shared traits!
I definitely agree, I just wonder if the binary notions of both can be shifted from the two circle model to a ven diagram model where there can be those overlapping ideals or if the model has to be thrown out with something new taking its place.
I think some just like expressing their gender and attempting to be the best version of it they can be. That can be compatible with others abolishing the concept for themselves. But also for those who feel strongly about their gender, abolition would involve a replacement that has the same function.