When they defend and promote the use of these drugs on kids, they show why they're called "transactivists" rather than 'trans advocates'. Anyone who believed in the concept of "trans kids" and was genuinely advocating for the well-being of children they consider "trans"*, would be appalled at the idea of using those same kids as guinea pigs.
Big pharma supplying drugs to be used off-label, thus evading responsibility when it all goes arse-up, clinics selling 'scrips via "informed consent" so as kids' rights are waived, shills all over the internet, in forums, on Twitter and YouTube, telling teens where to buy cheap 'blockers' and hormones online, coaching them in what to say, to who, to get what they want...
-They're the very people that real trans advocates should be campaigning against, in effort to protect those kids. Real advocates would be saying "This is not good enough! Our trans children deserve better!".
Transactivists, however, aren't advocates. Not for kids anyway.