gender issues are too big and complex to boil down to just a handful of concepts, but when you back up and look at a lot of the component problems that attach, i think one thing way down at the root is old fashioned misogyny.
it's kind of a vicious circle: people need to know and carry out their roles in the gender binary and when they do not, they need to be punished. fear of punishment leads people to want to be very, very certain who does and does not properly carry out their roles, which makes the roles more and more rigid.
women have to be kept in their place. women who step out of their place must be punished. worse, men who show any feminine characteristics must be punished into full personification of the male ideal and the male roles.
women can be sexually objectified for male gaze, or they can be scorned as being unworthy of male gaze.
and who is unworthy?
women who do not fit the "feminine" ideal.
but there's a greater shame than being a woman: being a man who is in some way "effeminate". and yes, i'm putting that in quotes because i don't think you can lump all behaviors and appearances neatly into categories by "masculine" and "feminine". it's more of a continuum than a binary and when we try to jam people into only two categories, bad things happen.
one of the bad things that happen is that people farther from the binary categorization get treated with contempt from both sides.
and this really only talks of gender roles without touching on gender identity that doesn't match a physical body or people of ambiguous gender to begin with.
but it isn't a zero-sum game. we do not need to strip dignity from anyone to give it to everyone.