Tambora's thread about biology vs. feelings opened up a whole new can of worms.
The overall gist of the opposition to the OP seems to be the claim that no one is objectively male or female. Biologically, no one is a man or a woman.
This, if true, is certainly news to me.
I suspect this would be news, too, to biologists.
So is this true? Does biological sex not exist, objectively?
It depends on what you mean by "biological sex". There are many aspects of sex and gender that are clearly, directly biological. And they aren't necessarily guaranteed to be consistent with each other.