user
The feminist viewpoint point is that gender is a spectrum of masculinity to femininity. A way of looking, acting or behaving in a socially constructed stereotypical way. It's socially constructed because gender roles vary across time, country and culture.
Since women have historically been assigned a feminine role, it plays to those who wish to take advantage.
Because it is a supporting role. It says you must be fuckable, sexually available, nurturing, compliant, a good housewife. Traditionally women were not thought capable of an education, or to hold positions of power because of their innate femininity making them unsuitable. Too feeble to be capable of voting. Considered hysterical and then incarcerated if they wanted to leave their husbands, etc.
So imposing the female gender stereotypical role on women is oppressive. The idea that it is innate is used as leverage. It is used as a tool and for every stereotypical feminine characteristic I can give you hundred women who don't have it.
And gender politics, particularly trans politics, enforces it. It says that gender is not imposed, it is innate. A man can innately feel as though he is a woman. He will present in a feminine way, act in feminine way, feel 'womanly' and therefore that must mean he is a woman. Not a feminine man. God forbid.
Which merely underpins the notion that (gender) roles are set, concrete and solid and women have them. All of them designed to make women take a supportive role. Whilst men get on with the real business of leadership, power and politics which is innate to them.
Sex on the other hand is innate It's identifiable, verifiable.
Women are oppressed because of their biology. Stereotypical gender roles are the means by which it's done.
Trans ideology completely contradicts things like gender fluidity though. Hence the lack of logic.