yes, that is the logical conclusion to what they are suggesting.
If they can't tell if you're male or female, what criteria do they suggest you use??
And if it's not normal, ordinary people's ideas, then what the fuck is it?
What would they actually say? Would you be able to say that a representative of the NHS has said sex is a nebulous concept that requires skilled expertise to determine, so what an earth makes them think an ordinary person would be able to grasp it??
This is one of the things that winds me up about this ideology. They claim you can't tell this, or that, or the other, and then absolutely bloody well rely on everybody being able to tell in order to leverage that knowledge.
Another example is being told you're homophobic, when they don't believe in homosexuality.
Men have every right to use the female changing room, when they can't tell you what female even means. Or men. Or men identifying as women.
they can be as coherent as you like, but they rely 100% on you not being, in order to push their incoherence.