The WHO's argument has hence far been cogent, your's has not.
You say that, but is it really?
The WHO have said that gender incongruence will no longer be a diagnosis listed under mental health in ICD11 which is not yet in use in any country and won't be in use in the UK until 2026 at the earliest*. Not only that, but ICD11 is a coding system. It isn't really used for anything else other than reporting to DOH and medical research. It's not a treatment and doesn't add any real clinical value to the record other than providing a method to get data from all records that match a given diagnosis. Not only that but current use of ICD10 in most systems require the codes to be crossmapped to SNOMED CT as that is the current coding standard for medical records, and under SNOMED it is categorised under Mental Health. Although again - that doesn't matter. The patient isn't interested in clinical coding - and for that matter neither is the doctor / psychiatrist / nurse etc. They don't even see the codes in some systems. They have just recorded that the patient has gender incongruence.
That said, I found an interesting article in Time magazine:-
“When you have a system that sets up someone’s very existence and identity in a diagnosis as a mental health condition, that feeds an enormous amount of stigma and drives people away,” Kyle Knight, researcher in the LGBT rights program at Human Rights Watch, tells TIME. “We have interviewed transgender people in Japan, Kazakhstan, Ukraine and Indonesia to name a few countries, and they don’t even want to begin to undergo the process of legal recognition because it requires them to go see a psychiatrist who will tell them they have a so-called mental disorder; something that they don’t feel corresponds with their own reality. People don’t feel like their gender identity is something diagnosable or needs a diagnosis.”
And yet, if you want to do something about your gender incongruence, there isn't anyone you can see to get treatment other than a psychiatrist in a Mental Health setting. So whilst a code has changed category, as I stated before - you still get referred to a gender identity clinic which will be run by a specialist Mental Health Trust. Your referral will still be on a Mental Health pathway and you will see Clinical Professionals trained in mental health.
If it is really not a mental health issue as the WHO state, then why is treatment needed and who will give that treatment, if mental health professionals are no longer appropriate?
I don't have a problem with the WHOs statement nor the change of category. It just doesn't really change anything at all, and certainly not for the patient.
*Based on my experience with the NHS and software upgrades I'd be surprised if it were implemented before 2030. Seriously. You have no idea just *how* slow it is to get change done in NHS software. Most systems aren't even using the current edition of ICD10!