Because they kill themselves. That’s why we give gender affirming care - because at best it just really can mess them up not to have it. And they were killing themselves. A lot.
So we came up with a protocol to do reversible puberty blockers for 4-6 years while they and their parents work with an endocrinologist and therapist to make sure this is the right call.
Only at 16 or 17 they then get the option for hormone therapy, and if they’ve been on puberty blockers then they either grow (or don’t grow) boobs naturally.
And unless they think there’s a high risk of suicide or self-mutilation otherwise (and there’s a process and a panel that needs to approve this) they can’t get bottom surgery until they’re at least 18 - assuming they even want it
We also do allow elective plastic surgery with parental and doctor approval - breast reduction or implants for example - at the age they’re eligible for hormone therapy.
Also, we give gender affirming plastic surgery to cis male teens and preteens who have manboobs, I think it can even be covered by insurance. It’s not unnatural or necessary unless they have a high risk for breast cancer, it’s purely because it makes them insecure