There's a lot of hair-splitting going on here over 'to what degree are sex/gender biological and/or socially-constructed categories', or that, as in the scientific paper Roberts quotes by Fausto-Sterling, in evolutionary terms cultural experience has physiological effects. Perhaps that's plausible. In fact, I find it fascinating. But these arguments seem to me at best a tilting at windmills (in the context of the political debate at least) and probably more accurately, a distraction from the core issue. And the core issue is this, and it works on a law of averages, statistical norms and factors which are typical, and to which there will always be exceptions.
Men are bigger than women. Men are stronger than women. Men are generally more aggressive than women (as borne out by statistics on violent crime). Men have greater muscle and bone density than women. The overwhelming majority of sex-offenders are male. Men are endowed with penises, and penises can be and often are weaponised against women. Moreover, they do this practically with impunity, given rape is under-reported and conviction rates are shamefully low. And 'intersex' is a rare condition, and as such an exception to these typical features.
Constructivism versus essentialism is an interesting debate, and it might even be possible to 'buy' the thesis of the effect of culture on biology. The point is that, in view of the above, it's irrelevant.
As a victim of rape, stalking and harrassment by males, I don't want to share intimate facilities with anyone endowed with a penis. And that objection is rooted in very good and valid reasons. Stating those reasons is not 'unkind'. Nor is stating I would like to find solutions which uphold the human rights of trans people without having to resort to extremes which endanger the very real, physical safety of women (the latter of which for me should always take precedence, as they are the more physically vulnerable category). Trans people protest that they are a tiny minority. Women are not - but we are the only majority who have traditionally been treated as a minority group.
No one seems to want to engage in productive debate on these terms. Rather, even if they're not crude enough to suggest de-platforming or posting threatening memes against the particular category of feminist they find so offensive, they will achieve the same result using 'gentler' language. Women are not being 'kind'. Deploy BLOCK.