I think this is massively overstating how widespread affirmation is, at all, and also lacking any assessment of what proportion of people is "some".
Along with that, the constantly repeated claim of puberty blockers being totally reversible (They are only in the medical sense, as in hormone production goes back to normal, but that claim still misses the fact that the time spent with reduced hormones has a measureable effect on the development of the child, as in, you won't "catch up" on puberty) is leading to more and more kids being treated with puberty blockers without a proper evaluation, because "there is no harm in it".
Yes it ought to happen between a professional and the person. And the real world is still a messy place where you can be influenced by non-professionals.
[1] https://www.dailysignal.com/2022/02/11/new-canadian-law-coul...
I don't think that is what is meant with the statement, but rather, that they mean the people are identifying as trans due to their peers, rather than actually being dysphoric.
As an anecdote, for me that's almost what happened, but I was just miserable for other reasons (depression). In todays climate of affirmation being seemingly the only socially acceptable choice, I likely would've started transitioning and become even more miserable.
This is one of the reasons why I REALLY dislike the current paradigm of affirmation first, rather than actually checking whether the problems are caused by dysphoria or something else.