Why are so many trans adults (and some other adults) so keen for children to alter their bodies?
In order to perpetuate the myth that all trans adults were 'born trans' and none of them are motivated in any way by sexual fetishism, it was essential to create the idea of 'trans children' in order to de-couple 'sex' from transgenderism.
This was made clear in a discussion in a now-deleted youtube video, in which a TRA said:
“I’ve always said there are two groups that are going to make change in transgender legislation and the “gender identity and expression” related language in legislation. It’s going to be trans youth because … they demystify it and take the sex right out of the trans experience.”
The other person responds:
“Right. And it’s hard to say no to kids, and the needs of kids and “keeping kids safe”. And you know, “being respected in schools” and things like that. It’s really hard for people to say no to that.”
More background to that quote here:
mirandayardley.com/en/this-is-an-all-out-political-war-the-gender-recognition-act-and-beyond/
If these 'trans children' were left to grow up naturally and grow out of their trans identification at puberty (as nearly all of them do if left alone), then the lie would quickly be exposed. So the trans identity has to be made permanent by the use of puberty blockers/hormones/surgery.
Since trans adults are (according to this narrative), just the adult versions of 'trans kids', it makes it harder to criticise the adults without implicitly also criticising 'trans children'.