I've only read the excerpt of the judgment above, but if it all hinges on "treated for all purposes as the being of the sex to which they have transitioned", then doesn't this immediately set a precedent which means all statistical recording of trans people falls foul of the law?
So statistics of violence against trans people will cease to exist, because violence against a person with a GRC must be recorded as violence to a person of their target sex?
Similarly, transmen must be called for prostate cancer screening, and not for breast cancer screening, and vice versa. How can trans people continue to receive hormone treatment or any other medical treatment to support their transition, after getting a GRC, since this treatment would now be incompatible with the law?
That line in the judgment doesn't say "must be referred to as the sex to which they have transitioned", it says "treated... as".