It's mind boggling, isn't it!
FWIW, I think some people are so caught up with the almost religious-fervour of gender identity ideology, and so many people they know and trust are saying the same things, then it must be true even if how they got the data isn't rigorous.
Their starting point is they believe that getting everyone to use de-sexed language is a GOOD THING, for example. Then, a report from people they like as they are on the'right side' of what they see as a good and righteous fight comes out, that appears to confirm this.
Their instincts are to do what they can to spread this message, not to interrogate the methodology as the results are in line with what they believe.
This is confirmation bias in action, of course, and why peer review matters, and why it matters that HCPs in the NHS can be confident their practice is based on a solid evidence base, not lobby group propaganda.
It's depressing that we're having to remind the NHS about this, AGAIN.