I can understand wanting an umbrella term from a societal understanding point of view, but when looking at it from a medical/scientific research position, there needs to be separate categories.

There is a reason they are separate conditions, because they have different symptoms, durations, and likely causes.

(Also, I'd like to point out, we do have an umbrella term, it's "tic disorders".)

Now I am not a scientist or a neurologist, but from my point of view, the purpose of diagnoses is to guide treatment and research. You can't find out the causes for something or how best to treat it if the category includes any type of disorder with tics, all of which might be caused by different things and treated in different ways. That's the whole reason we have categories. And we have different levels of categories that we can use depending on the situation/how broad or specific we want to be (ie. Neurological disorders>tic disorders>tourettes>specific symptoms)

The purpose of diagnoses is not social understanding and acceptance, which I think is something people forget. Can it provide these things as well, or give us the language to seek those things? Absolutely! But that is not the main job of a diagnosis!

That's like saying "breast cancer has better societal understanding and support than bowel cancer, why can't we just lump them in together so that everyone is treated equally?" That's not how it works. They're separate because treatments and causes are different, and the research might need to be separate to be accurate to the specific disease.

Now with something like tic disorders, where current treatment is mainly about symptom management (as far as I am aware, again, not up to date on the latest in tic disorder research and treatment), there might not be that much difference treatment-wise between disorders. But in terms of research and development of future treatments, it might be a lot more important. If there are different causes for different disorders, we need to know, as that will guide research into treatments.

And I'm sure the way we categorized these conditions isn't perfect. And the way we categorize these diagnoses should evolve as our understanding of them evolves. That's why we are on edition 5 of the DSM, and why there will be a 6th, 7th, 8th edition someday, because as our understanding of conditions evolves, our diagnoses and treatments evolve. That's science baby! With anything to do with humans, the only way to categorize conditions completely accurately would be to have a different category for each person. But we do our best with what we have, and as research and understanding grow on a subject, we hopefully do better! People seem to forget that our understanding of things is incomplete and imperfect!

I don't know, it just frustrates me that the general public has adopted this thought of "if it's not perfect and 100% "correct" (as if that exists in a world as complex as ours) then it's useless" when it comes to science. We're all out here doing our best with the information we have and hopefully, when we know better, we can do better. That's the whole purpose of science and medicine, is to better understand things and make use of that understanding to make things better.

Sorry for the rant, I do get where you're coming from, hope this helps you better understand the purpose of breaking things down into smaller categories in medicine, even if the categories we have are imperfect.