To me at least, your first paragraph about everyone getting huffy and writing letters is the expected outcome and exactly the kind of impassioned Socratic debat

To me at least, your first paragraph about everyone getting huffy and writing letters is the expected outcome and exactly the kind of impassioned Socratic debate that's good for the field. The term used to describe those with intellectual disabilities has changed a bunch of times in response to the term being picked up as a pejorative; I can't imagine people would be too up in arms about that happening to "mental illness." The debate with more meat is what categories exist, their defining characteristics, and where different experiences fall, not that the category that used to be called mental illness is now called "harshed brain vibes." I think the difficult issue is that gender dysphoria occupies a similar space to neurodivergence where the line between "this is a problem that needs corrected" and "this is a kind of person that needs accommodation" is heavily influenced by cultural attitudes, and while the difference isn't arbitrary we have more examples than we can shake a stick at from history where psychology has persisted the wrong view (usually the former when it's the latter) for many many years.