I agree with @MrsOvertonsWindow and @WallaceinAnderland
I'm a Feminist. I focus on the challenges, risks and inequalities female people face because of our bodies. Some of these are directly down to physical differences between us and men. Many more are down to how millenia of patriarchy has shaped society's expectations, understanding and treatment of us. Between the two are the ways our unavoidable physical and reproductive differences are or are not accomodated in society's structures and norms.
The only reasons I have any issue with Genderism is that (1) in redefining woman as a mixed sex mentality it disconnects female people from our history, our shared experiences and the language and political and social understanding we need to fight this exploitation, abuse and marginalisation, and (2) the incoherent in/out hokey cokey of "my-mind-sets-my-gender-not-my-body-and-it's-not-about-sex-and-sex-is-more-than-binary-but-its-essential-that-I-adjust-my-body-to-fit-my-gender" is causing real people, many far too young to appreciate the impact, to make real, irreversible, damaging changes to their body.
I realised a while back that reacting to Genderists latest flip flop is just letting them set the reference points. Actually their reference points are irrelevant to me. My reference point is the people with female bodies, what that means for us, and how to fight and defeat the unfair burdens we bear because of it.
It doesn't matter if gender is a real thing or not. It doesn't matter if sex is binary or not. I'm not here to argue about the edge cases. I'm here for the pretty much 50% of humanity that is recognised as female the day we are born and live with the consequences of that the rest of our lives.
Understanding that that is what matters to me gives me an unshakeable foundation to base any argument on.