I guess that it's reasonable to include the issue of de-transition and regret about transitioning in discussions about gender affirming care.
The first problem is that the research is so polarized that a lot of people don't even want it to be done. There was one totally bogus study that claimed that 85% of people who transition express regret. That's not true and the methodology seems to be intentionally flawed. On the other end, activists like to claim that it's 1%. 1% is definitely closer to reality. Still, numbers in the USA range from 1% to 5%.
The thing is, from my perspective, when it comes to adults deciding to transition, I don't care if it's 85% or .001%. If you're an adult, you can do what you want with your body. There are some things that people should be cautioned against doing at any age; but, I'm not gonna get the government involved or lift my own finger to stop an adult from making a decision about his or her own body.
As usual, kids are a different issue. It's also the only reason why de-transition numbers matter at all. It's also where a lot of people start cooking their books to support their agendas.
The only way to get that ultra low number of people who regret transition is to not isolate children in the analysis and also to only include people who transition. Well more than half of children who experience gender dysphoria stop desiring to live life as the opposite sex by the time they hit puberty. Most of the activists seem to be the kind of people who would call "transphobia" on people who express concern on clinics performing double mastectomies on twelve year-old girls and putting children on puberty blockers and hormones; yet, those are precisely the people who are most likely to regret transitioning. There's also an element of what would happen if the activists got their way and we stopped bothering with due diligence and psychological analysis before going ahead with surgeries and therapy - the number of people regretting the transition is bound to skyrocket.
Still, all that said, I don't care how low the numbers are, it's wrong to chemically sterilize kids. There are even adults who don't regret transition but for the fact that they were inadequately informed about the long-term effects of the hormone treatments and they ended up permanently sterilized. At least with adults, although I can and do feel sorry for them, it was their decision. With kids, I don't care how carefully and how often you explain to your twelve year-old that he or she might never be able to have kids, it's still wrong to leave that decision to a kid.
When it comes to kids with gender dysphoria, we can get the numbers who regret transitioning down by being loving and supportive and letting them live their lives while withholding permanent, life-altering procedures until adulthood. Even if the fifteen year-old trans boy who already went through menopause will always be happy living as a boy, as I hope he is, we can't forget that his choice to have children had already been made in adolescence and probably made for him.
Bottom line, no matter how you put it, there's no justification for medically transitioning children and it mystifies me that so many people so passionately want to transition kids rather than just being loving and supportive and letting their kids do what makes them happy without inflicting irreversible damage.