Let's assume for the sake of argument that we're not talking about inaccurate findings, and we're also not talking about accurate findings being misinterpreted for political reasons or whatever.
If science were to find that trans people are actually confused somehow, then it would need to find a better solution than transitioning before anyone could say "we shouldn't support transitioning".
...and if it did find a better, happier solution, wouldn't you want to investigate that? I know I would.
For most of my life, I believed (because that seemed to be where the evidence pointed) that gender was entirely a social construct -- something you were socialized into -- and the idea of wanting to be a different gender than you "are" was a contradiction in terms.
...and I didn't want to believe that gender could actually be an innate property, because that would mean that girls were innately different from me in some way, and I absolutely did not want that.
...but then it turns out that gender is innate to some degree, and not necessarily correlated to your genitals or your chromosomes -- and hey, I'm actually a girl, brainwise; I just didn't look like it on the outside.
The truth sets us free.