Even if you were to convince me of this legal fiction that gender identity has nothing to do with idemitiy and is in fact just a medical condition the Supreme Court doesn't care to treat, I still would call it a life threatening attack.
If the Supreme Court denied chemotherapy for cancer patients, it'd be perfectly justified to call it life threatening denial of care. The fact that it's available for cancer patients with other diseases that are treatable via chemotherapy is irrelevant.
It should be up to a doctor to decide if a prescription makes sense for a particular patients symptoms and diagnosis. The Supreme Court should not concern itself otherwise.
At least with Roe v Wade there's an argument to be made about it involving a second hypothetical person. But this? This is strictly between patients, their medical care, and their parents.
But I guess what you’re saying is why is the state passing these laws, which is a fair enough question. The Supreme Court says they are allowed to, and they are the authority on which laws are allowed, so I expect the states will keep doing this sort of thing until the voters tell them not to.
Plato did try to warn us that democracy was a terrible idea.