Look. It's very simple.
Of course social constructs can be real, or at least have real consequences. After all, plenty of architectural womders have been built and atrocities and wars committed for gods who probably don't exist beyond a social construct.
Indeed, a key insight of Feminism was exactly that there is a difference between the fact of being female and the social constructs laid on top of that fact. We understood that way before Genderist activism. We knew how those constructs placed expectations on and about female people and that had (and still has) very real consequences for us, often far more than the consequences of our physical differences to men.
Indeed, you could very easily make the arguments that Sexism is basically a collective noun for the consequences of Gender constructs being applied on top of sex.
That's exactly why we reject a social movement that frames gender as more significant than sex. Because to a Feminist, Gender constructs are the mechanism through which sexism and misogyny get enforced and replicated.
But consuder: if sex isn't gender then gender isn't sex.
And if gender isn't sex then there is and never has been any justification to change the language of sex to label gender identity.
And there certainly isn't any justification to point at things created for female people, point at the word "woman" and say basically "yeah but we decided woman means something different now so that means these things must have been supposed to be for our new "women" instead".
If Genderists really believed in Gender as something real and meaningful they wouldn't be trying to hide it under language. They'd give it its own language to show it isn't sex and talk about it plainly.
But they don't. They play a double game where sex isn't gender when it comes to arguing that male people are "women" or female are "men", but gender is sex when it comes to arguing that female people are irrational to say to to trans women's inclusion in clearly sex-based concerns like provision of intimate care.
Amd the fact they don't is all anyone really needs to see to understand this movement is not an honest one.