Right.
Then it has as much meaning as me saying I am a Flerbit.
What is a Flerbit, you ask? It's nothing to do with the physical body and it's also nothing to do with traits, clothes, preferences, stereotypes. It's personal. If you are a Flerbit, you just know you are. That's it.
Also, because I am a Flerbit I should be able to play on under-8s sports teams, join primary school children in the classroom and on school trips without needing a DBS check etc. etc.
Ah, you may say, so a Flerbit is something to do with age and someone who thinks they are under 8 years of age? BUT NO! Flerbit and age are separate things!
NONETHELESS, because I am a Flerbit I should be entitled to things that 8 year olds are entitled to.
But not because I think I have only lived for 8 years or appear to be 8 years old or have anything in common with 8 year olds in terms of interests, preferences, feelings or stereotypes.
But because I'm a Flerbit.
Keep up.
Anyway, just trust me (and give me the things).
By your reasoning, prior claiming a trans identity should be taken into account in law, policy and reasoning to exactly the same extent as Flerbits. That it's to say, they have every right to think of themselves as they like, they shouldn't be harrassed or denied housing, service in shops or employment (like any other person holding an unverifable personal belief system) but that's absolutely it.
The idea that you'd work this sort of subjective, undefineable, unverifiable flim-flam belief into legal definitions, reasoning or policy designed to guard against real world harm - much less require anyone on pain of prosecution to respect or join in such a belief - is absolutely bonkers.
(Flerbits unite)