Yes I've also made that analogy to "late term abortions". They both operate on a tiny bit of truth that is highly misleading.
Yes in rare cases women have abortions late in pregnancy. But they are often due to detection of fetal anomalies or high-risk pregnancies.
Likewise the rare cases of gender affirming surgery in children are generally in jurisdictions where the age of majority is lower. Done after established gender dysphoria and treatment. And generally top surgery, not bottom surgery.
Why do people never view the absence of treatment here as an irreversible cost? For a person experiencing gender dysphoria that is what puberty is to them.