So you are saying that someone with complete androgen insensitivity syndrome should use the men's bathroom, even though they have fully female genetalia?
Huh? Nobody made any statements about bathroom usage or such, nor has the UK ruling anything to do with bathroom access. We are discussing the definition of sex and how the court ruling came to the conclusion .
To be clear, that's not what this ruling says, that would be a consequence of other laws that can be changed if there's political will. The ruling is just a narrow definition for legal purposes of what the words "Man" and "Woman" mean. If a law is passed allowing for gender identity to be on a passport, then you could have someone who was afab put "Male" on the passport if they're trans.
And if such a law isn't passed, or a law explicitly banning that is passed, then *that law* is the issue, not the definition of sex dictated by biology. Remember, sex and gender are not the same.