You can't be a gender critical feminist.
There is a conversation in contemporary feminist spaces, even progressive feminist spaces, about a perceived conflict between cisgender and transgender women's rights. This underlines the core thesis of many women who identify as feminists while opposing trans inclusion. There is also a broad sense that trans inclusion ends at civility and tolerance - that respecting a trans woman's pronouns, granting her permission to go about her day-to-day life unharmed and nominally supporting basic discrimination and healthcare protections is the ceiling of reasonable allyship. A large swath of so-called trans allied feminists identify as such while maintaining that trans women are not the same as cis women, are not as authentic as cis women or even women in the way cis women are. The difference between outright transphobia and exclusionary tolerance is not one of substance, but volume.
At the centre of both the outright rejection and quiet alienation of trans women is a series of anxieties - the perceived social and political necessity to police a bounded site of struggle for feminist activism, the notion that womanhood or femininity is defined by a universal cisgender girlhood, and a conception of womanhood as a conscripted, involuntary biological cage. These are often cited as the broad theoretical grounds to justify erasing trans women within the context of women's spaces, rights and struggles. All three anxieties directly reflect pervasive patriarchal myths. There is no such thing as a feminist who does not authentically recognize trans women as women; to do so is, by definition, to oppose the cause of women's liberation.
These anxieties require the presupposition of foundational pillars of patriarchy. The notion that liberation is a zero-sum game, the notion that biological sex is an inherent essence but gender requires careful performance and patriarchal consent, and the notion that women have no agency over their own oppression have maintained patriarchy since time immemorial. At its core, all three rely on an insidious play upon human nature and the inherent neoliberal meritocracy which underlies contemporary western society. One of the first myths a patriarchal-capitalist society imposes on its subjects is the idea of the just world - that with sufficient effort, perfect performance and adherence to the dominant patriarchal script, you will be loved, spared and protected.
Such a paradigm is uniquely helpful to the perpetuation of patriarchal supremacy, because it prompts the internalization of all systemic suffering. Sexism becomes a matter of personal fault and inadequacy. When confronted with the realization that no amount of compliance exempts one from patriarchal violence, accepting the patriarchal myth entirely and retreating to a defensive bio-essentialism is often easier than the alternative. Acknowledging patriarchy as a structural system of power imposed upon the social relational category of women by men requires solidarity with women with less privilege - it requires genuine humility, the prioritization of the collective over the self and abandoning the relative safety of feeling better than other women. Instead, by opting to see womanhood as an inescapable trap of suffering on the basis of natal misfortune, patriarchy becomes something to optimize for and overcome without worrying for others. This view surrenders the dream of true feminist liberation in favour of perpetual damage mitigation alone - and damage mitigation always requires choosing who to cut from the lifeboat.
Patriarchy's oldest and greatest lie was that womanhood can be revoked. That if you're too loud, or too bossy, or not accommodating enough, if you're not pretty enough, not thin enough, not good enough at makeup or cosmetics, that if you act out of turn, speak out of turn, live out of turn, that if you're not kind enough or caring enough or meek enough or selfless enough, you are not a valid woman. It is the same line that has been levied at Black women, Indigenous women, poor women, queer women, and now trans women. In broad discourse, there is constantly accusation after accusation levied against trans women as a collective for the actions, real or imagined, of individuals, as there always has been when patriarchy wishes women to tear each other apart. A selfish woman, a lazy woman, an entitled woman, a woman with deeply internalized misogyny and a woman who didn't grow up around women - all of these are still women. Asking for accountability is not the same thing as stripping humanity. Just as declaring that a selfish cis woman is less valid as a woman is sexist, declaring a trans woman is less of a woman for her poor behaviour is identically sexist. Trans women are women, and women are not perfect. Women are people - messy, complicated, and very real people.
True liberation must begin with the abandonment of this defensive crouch which so many women adopt in part or in whole in order to avoid the existential dread of acknowledging that patriarchy is a goliath system of power, coercion and lies that nevertheless can and must be fought. Liberation begins with the acknowledgement that liberation is not a zero-sum game - that no women are free until all women are free. It begins with the acknowledgement that a universal girlhood does not exist; that a girl in suburban New Jersey with progressive parents in a queer-friendly school does not have the same childhood, struggles or socialization as a Brazilian girl in a Catholic-conservative family outside Rio de Janeiro, and yet both are still girls. It begins with the acknowledgement that women are powerful - that we have agency, that our lives are defined by more than just suffering, but by joy and freedom and creativity and care. It begins with the acknowledgement that trans women are, inextricably, irrefutably, unreservedly women.