What's happened to Jazz, and Jackie Green and all the other similar cases, is beyond my comprehension. We have two children, a few years older than Jazz. If we had had concerns about either of them when they were very young, we'd have sought medical advice but we wouldn't just have accepted uncritically anything that seemed odd or counter-intuitive. We'd have wanted a lot of assurance that what we were being advised was backed up by good research and years of success in clinical practice.
If Jazz's parents had done this, back in the very early 2000s (Jazz was born in 2000) my understanding is that they would have found out that the standard treatment for gender dysphoria in children and teenagers in preceding decades was watchful waiting, not social transition, and certainly not disrupting their normal hormones or putting them through surgery.
They would have been told that research showed that in most cases gender dysphoria resolved once the child was through puberty, i.e. the dysphoric child became a non-dysphoric adult who was no longer distressed by their sexed body.
They would also have been told that in a tiny handful of cases the dysphoria continued into adult life, and in that case, the adult might decide, after years of counselling and therapy, to take artificial hormones and/or have surgery, but that only a minority of dysphoric adult men did this, and the outcomes weren't great (in any respect, physically or psychologically or socially).
Articles about the Dutch puberty blocker protocol started to be published at the very end of the 1990s, so that was still very experimental when Jazz was first taken to a gender specialist.
I've never watched I am Jazz but I gather that one of the first gender 'experts' consulted was a relative. Is this even ethical? It may well have been a factor in why the parents went along with the medical intervention route.
Malcolm Clark has a trenchant article on Jazz here. https://www.spiked-online.com/2023/08/20/the-tragedy-of-jazz-jennings/
Article about I am Jazz from several years ago by an endocrinologist. A voice in the wilderness in the US, sadly. https://www.thepublicdiscourse.com/2018/04/21220/?fbclid=IwAR3rD5yqhydMeHdyaOxrXmx8c-rStXursNyZFRR0Hr6A-9C82fiP2VTev1g