I think you are responding to things people haven't said.
In regards to "reversable hormone-blocking", I think it is unfortunately being promoted ahead of research based evidence. From the recent systematic review:
https://www.ncbi.nlm.nih.gov/pubmed/29514975
While it seems rational in hindsight for a "persister", what are the effects on the majority that end up "desister"?
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5290172/
There is just so much that we don't know, but are leaping forward with.
That highlighted part is really important in the light of recent developments.
Studies carried out a decade or more ago show that about 80% to 90% of non gender conforming children grow out of it, usually when going through puberty. It also appears that there is no reliable way to tell which are the ones who will persist. There's a lot about that in the Bailey and Blanchard article I linked to above. However, what is now happening is that these children are being socially transitioned as soon as they express a preference for the wrong toys, and then put on puberty blockers with the assurance that these are "fully reversible".
The problem is that they're not harmless, as you point out, with implications for bone density, IQ level and possibly even later cancer risk, but nobody has followed this up. (In contrast, women having a difficult menopause now find it almost impossible to access HRT because of a huge study that was done after the treatment was in widespread use which showed a small statistical increase in the risk of certain types of breast cancer.) And the other problem is that when the children are given these drugs, they
don't desist. Not going through puberty prevents the brain maturing and sorting this stuff out. Nearly all children put on puberty blockers now are progressing to cross-sex hormones. Which will sterilise them and cause absolutely irreversible changes to their bodies.
Twenty, even ten years ago, when sex reassignment was something only embarked on after a lot of assessment and soul-searching to try to be sure it was the right thing for the individual, regret and detransition were extremely rare. Some therapists working in the field had never seen a case. Now, however, there is a sharp increase in regret and detransition.
These stories can be found on the internet. Some are men who realised that living as a woman hadn't solved all their problems and indeed had created more, and decided to stop "living a lie". Most of the recent cases seem to be young women who were adamant that they were boys as adolescents but realised some years later that they really weren't. They're now trying to be women, but with baritone voices, beards, double mastectomies and male pattern baldness.
One academic at Bath Spa university noticed this trend and wanted to study it in more detail. He was shut down by the university after a campaign by trans rights activists. His crowdfunding page is here,
https://www.crowdjustice.com/case/free-speech-matters-round2/, and just google "Bath Spa university transgender" to find a ton of articles about the case.
What is happening is that trans rights activists are absolutely adamant that
nobody desists after identifying as trans, and that any research into possible desistence is transphobic, aimed at deterring people from identifying as trans. They are an extremely powerful lobby group, having influenced a lot of what is now going on in politics and medicine. They co-ordinate to bombard any organisation seen to be co-operating with people they don't like with allegations of transphobia and hate speech, and if Bath Spa university has caved, who won't? (Certainly not Milwall football club, who were warned by the women's organisation who booked a room for a meeting that they would probably be targeted, said "don't worry, we won't give in," then cancelled the booking after experiencing a torrent of furious complaints. "We've never seen anything like it.")
Powerful hormones are being given to children with no long-term follow-up and no hard information about risks of such things as cancer or osteoporosis in later life. Even proposing to research these potential risks is hounded as transphobic. The ostensible reason is, "If we don't give the children the hormones they'll kill themselves," which is absolutely false (see statistics on known patterns of desistance) and against every recommendation by organisations such as the Samaritans who deal with vulnerable suicidal groups. It has got to the point where children are crying that they must have the hormones because they've been told (by Mermaids and other trans-youth organisations) that they'll kill themselves if they don't get them, and they don't want to kill themselves! (Some of these children are probably using the threat of suicide to get what they want, but others are genuinely scared of becoming suicidal because of what they're being told.)
This is one hell of a mess and the only people who will do well out of the fall-out are the lawyers.