Gender affirming surgery isnt uncommon at all in minors, but it is usually for straight children: breast reduction/augmentation, and much much more rarely genital and cosmetic surgeries, and even all of those aren't for transgender children.
Also here's a source, not like you need one as it's fairly common knowledge and easy to find, but maybe someone reading is looking for one. https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2808707
To your point though, yes, it's a boogyman.
New Zealand requires eligible voters to register but not to vote. It's also not enforced though.