I think the problem comes when it’s framed as “you can only be trans if you have a diagnosis” as opposed to “you’re trans whether you have a diagnosis or any kind of medical experience with it or not.” One can say “it took a doctor diagnosing me with dysphoria before I could accept I was trans, but I understand that this is just my experience, and I know others have their own experience” and that’s totally fine.
It should be ok to tell people, for example, that dysphoria is central to the trans condition
I don’t agree. It’s ok to say “dysphoria is central to my trans experience, though I understand this isn’t universal.” That doesn’t gatekeep anyone. In fact it’s the opposite. But it’s not ok to tell others that dysphoria or medical treatment is required to be trans.
Sure, in many locations, having a diagnosis is required before doctors will allow you to even begin HRT or consider having surgeries if you want them. But that’s just a symptom of a broken medical system that enforces cisheteronormativity, and prevents self-ID and informed consent. It’s not what actually defines what being trans is all about. It’s just a hoop people are forced to jump through.
There’s a difference between having honest and good-faith discussions about the role dysphoria, surgery and HRT play in the overall trans experience, and making broad definitive statements. That’s what actually erases others’ experiences.