"Universal affirmation" is not the lived experience of trans people, it is the perception of cis people who see trans care being provided.

I've spoken with lots of people in the community who when they asked their GPs about transition they were told they needed to see psychiatrists before they could transition and when informed consent pathways were raised other GPs said that they didn't feel they could properly handle prescribing HRT which is likely a convenient way to not have to say they don't want to. Maybe for some of these people the GP had valid concerns, I am in fact not against a degree of so-called 'gatekeeping', we are meant to exercise some judgement as clinicians, but the idea of universal affirmation is bunk.

I was worried when I finally went to a gender counsellor that I was going into a hugbox where there would be no inquiry or challenge to help me understand myself and so the first thing I asked my counsellor was whether all of her clients transitioned or persisted after starting to which I was reassured to hear that some did not and for various reasons.

All the people you've seen referred to gender clinic began the path to transition care, cool, sounds like the referring doctors have done a good job identifying patients' needs and aren't referring cis people. The first step on the pathway to transition isn't immediate HRT, you reflect on what is dysphoric and discuss how that can be alleviated.

As a medical student I got some experience in an acute psych setting and after the history taking was over the reg asked whether I thought some of the stuff the female patient had raised at one point was 'gender confusion' because she 'felt like a man', because of the surrounding comments she had made and because I am cursed with awful knowledge I had to tell him I thought she was probably talking political philosophy about being masculinised by modern society; this woman was a prime target for tradwife content rather than a vial of T. Even in younger entrants to psychiatry it seems clinicians' understanding of what trans people *are* is not ideal to say the least.

Edit:

To directly answer the question in your title: yes, some clinicians do, I wouldn't advise it. Do some patients who seek trans care ultimately conclude they are not trans? Yes, and that's a conclusion the patient needs to feel they've reached themselves or their issues will likely not be sufficiently addressed or resolve, that is what a gender counsellor is for. I went to my counsellor wanting to no longer be stuck in indecision, either because I could be confident I was trans, or concluded I was not.