Why would you want to prevent the collection of data that would demonstrate the value of treatment you are confident is 'clinically necessary'? Surely you'd be celebrating the chance to show the world how lifesaving these treatments are?
It is horrifying that this research doesn't already exist, given that GIDS have been prescribed puberty blockers to children in the UK since 2016. But they did not collect any follow up data. The evidence base should already exist, either demonstrating that these treatments confer benefit, or that they don't, and also demonstrating what, if any harms are being done.
Mermaids should be howling about the fact that this data hasn't already been collected and analysed instead of suggesting that research shouldn't happen now.