I think you’ve made some errors here. It’s less that male and female are constructs as that “woman” and “man” are constructs—and that’s very different.

Secondly, you draw a conclusion without showing how you arrived at it when you say that nothing has concrete meaning and therefore this is bad for trans people. (Or something to that effect—I can’t see it anymore while I’m commenting.) The idea that nothing is concretely real or true in some authoritative way is important to bring people to a place of humility and non-fundamentalism. It doesn’t have to be True to be something we work with.

Right now, we have a lot of people trying to control the invention of “woman.” Even though it’s an invention, they are saying, “No! You don’t get to co-create this invention! Our invention is True and your invention is False.” It’s astounding how they don’t see the childish hypocrisy here. But it’s in part because they think that “female” and “woman” are synonymous. And since “female” is a biological definition, then biology must define “woman,” as well. But biology is the sole determiner of “woman” like it’s the sole determiner of “mother”—which is not at all.