I understand where you’re coming from, and that type of thing also makes me uncomfortable (related: when friends have babies near the same age and talk about how one day their kids might get married. SUPER WEIRD Y’ALL) but there are very good reasons why it’s a wonderful thing to diagnose at an early age. First, though, the diagnoses is a lot more than just “kid likes dolls and long hair”. It’s so much more than that, and you’re marginalizing the real experiences and difficulties of trans people when you reduce it to something so superficial.
As I said earlier, going through puberty as the wrong gender is unbelievably difficult for these kids. It’s hard enough for a child who is certain she’s a girl to look down and see a penis there, but when the secondary sex characteristics start coming, it can be devastating. And, as I said, these changes are not easily undone. Thicker bones, an adam’s apple, a deeper voice, facial hair… these are things that can keep a woman from successfully transitioning. The effects of testosterone on the body during puberty are amazing, and some of them are pretty irreversible. Do you really feel comfortable telling a girl she has to go through that experience, and carry the scars of it all her life, just because you feel weirded out by kids being diagnosed young? And, obviously, female puberty is no picnic either, even though the changes are easier to reverse later.
Then you get into the psychological effects. There are children coming of age now who were diagnosed young and have lived all their lives as their correct gender. If you look at their lives, and compare them to people who had to wait until adulthood to transition, there’s just no denying that starting younger is the way to go. They never have to “transition” at all! They just grow up happily. They never internalize that self-hatred. They may have the wrong genitals, but they have support from their families and therapists, and they are secure and healthy. It’s a beautiful, wonderful thing.
I really do understand where you’re coming from. But just like it makes no sense to tell a young man coming out at the age of, say, 12 that he needs to sleep with a few women before he really knows’, it makes no sense (and is really quite cruel) to tell a young trans child they need to grow up before they really know if they’re a boy or a girl. And when it’s done to make sure a bunch of grown-ups on a messageboard don’t feel uncomfortable, it’s just disgusting.