It's the same black and white zero sum thinking that characterises the spaces debate: third ways unacceptable.
The judgement does not refuse pbs, but requires an objective court of protection to establish it is in the child's best interests and they are able to consent. Remove the need for the child to be able to understand consequences fully as a child (and as I keep saying, we have evidence of adults posting on MN in defense of pbs being prescribed who are unable to engage with or acknowledge the facts beyond denial so the judgement seems very reasonable that a child will not be able to do it) and what is left is best interests.
Precedent in situations that involve serious effects on a child are usually based on the minimally invasive and restrictive. There are many less invasive ways to treat a child with severe dysphoria and self harming ideation, which is what this was about in the first place: that psychological supports are essential and should be the main plank of treatment. Self harming and suicidal ideation are also high for children with autism and anorexia, but there is no pbs silver bullet for them, so other treatments, strategies and resources are considered best practice for treating those children and supporting those families in this situation.
If the argument is about the emotional harm and risks then there are many other ways to help; pbs are not the only answer to emotional and psychological distress, and are not the least invasive or permanently altering.
If an adult child takes parents and doctors to court over a kidney transplant or an amputated limb that parents consented to on their behalf as a child, the evidence will be fairly straight forward to show that the harm of not acting would have significantly out weighed the harm of the treatment, and adults made the best decision possible in the circumstances.
This is the line of argument trying to be applied to pbs. That the harm of not acting outweighs.
The issue is that while a septic foot with no circulation will not recover and will end up causing death, and that is a known, objective, scientific, evidenced fact that the same medics looking at the same scans and evidence could replicate diagnosis of, there are many less invasive ways to treat suicidal ideation that do not involve causing permanent lifetime harm. No one can say that the child would not have recovered equally well on other less permanently altering treatments. No one can say that the adult child's distress at their altered body and lifetime of medical needs and infertility was absolutely the only possible solution to their dysphoria and the risk it was causing them when they were a child. Keira evidences this.
Likewise, no one can currently say how many of these children, if supported in other ways and allowed to go through puberty, would either find their dysphoria resolved, or become happily trans as adults as Sharpe has done without the risk of harm caused to a growing body.