Interesting link, thanks.
I wonder if the fact that it's all women is an artifact of them more likely to meet and befriend (and thus form a group with) other women, or if detransitioning is actually more common among women & girls. Perhaps someone has actually measured.
There's been some preliminary work done on this, by both Lisa Littman and Abigail Shrier. While nothing is 100% solid, there are a couple of hypotheses that I find plausible.
One is that these are pubescent females who are
fleeing womanhood. We currently have a pretty heavily pornified culture, and the amount of sexism and misogyny out there has
increased since I was a young woman. The pressure on young females to perform sexually, especially with respect to sex acts that are painful or harmful, has increased massively, and there's quite a bit of harassment of females as "prude" and "outdated" if they say no to things like anal sex or choking. Add in the rather dramatic change in the life of a young female when they start growing breasts, and I'm not surprised that many of them wish to "opt out" of it altogether. Hell, if there'd been a way to sidestep all of that when I was younger, I might well have taken it. There's nothing like being a 12 year old and being incredibly self-conscious because adult males won't stop ogling your breasts and butt to make a young female really uncomfortable in their body. And having a middle-aged man throw torn out pages of porn at you and asking if 14-year-old you wants to "give that a try" with them really makes a female's sexed body seem like a torturous prison.
The other hypothesis has to do with social contagion, something that is massively more common in teenaged females than in males. It was one of the vectors in repressed memories of childhood sex abuse, ritual satanic abuse, anorexia, and cutting. I don't really understand the drivers behind it, but it's definitely a thing, and it seems that identifying as transgender among teen females is very likely to be part of the same phenomenon.
The latter hypothesis is reinforced by the recent rise in young females self-diagnosing as having Dissociative Identity Disorder... which is happening in real time now. It's very strange.