Why do we think that?
Gender dysphoria is not simply living your life as the other gender (which you seem to agree with), but rather it's any discomfort and distressed caused by that. An analogy to gender dysphoria might be depression. Some folks might have none, some might have a mild case, and others might have extreme cases.
So, I don't agree that they had to have experienced that at some point in their life - although I will concede that most probably have.
But by that analogy, like 1/3 of Americans are still mentally ill because of depression alone. So, while technical true, it feels like disingenuous framing given the original context I was responding to that these people are looney tunes.
I tend to think it's often a bit more hypothetical than actual, but I understand your point and agree more than I don't.
I will be honest, I don't know enough about hormone blockers, but the frontier study looks super shaky (ridiculously small sample size, data from the 70s, missing data according to footnotes, etc) and the other looks valid enough that I assume it's correct (although it's kinda just a lady's opinion but she's pro, so lets go with it). She seems to think there are some irreversible effects, and if that ends up true, I agree with you.
My initial reaction has always been that doctors shouldn't prescribe anything to kids that does permanent damage, and the surgery rules should be the same rules as fake tits for girls (whatever that is I think its 18+). Seems like we might agree on that.