Yes, there’s a lot of truth to this. If we fall into the trap of trying to prove the legitimacy of transgender people based on individual cases, what do we do when someone’s experience doesn’t fit that narrative? Should an example of a transgender person “detransitioning” be used as a reason to deny someone else sex transition surgery? Obviously not, but these are the kind of problems we can get into by overgeneralizing.
That said, people respond to stories, and we would not be where we are with transgender rights — or even gay rights, for that matter — if people didn’t vicariously experience & understand the injustices they’ve suffered through stories like these. I suppose sometimes the best truth is not to say “gender is this” or “gender is that” but simply: “life is probably more complicated than we think.”