>This is why the type of disability activism you see in identity politics is usually limited to mental illnesses
You are using the term "mental illness" in a way that seems to exclude people for whom it is obviously a disability. These people are characterized by:
1. One or more hospitalizations that are not voluntary.
2. Diagnosis by medical professionals, not psychologists or oneself.
3. Having to take medications forever, at least in order to be employable or generally take care of themselves, that cause substantial long term effects including diabetes, brain damage, disfiguring tics and involuntary movements, recurring tumors, sudden death, and other problems.
The people you are thinking of, who act like it is possible to normalize and be open about mental illness, are, let's say "type A", while I have defined above what I'll call "type B".
I just want to call your attention to the fact that "type B" people are erased as much or more by "type A" as the visibly disabled that you acknowledge. You are inadvertently promoting that erasure.
"Type B" people bridge both worlds but can't talk about it normally. I do recognize the emotions regarding "type A". I recognize why they do what they do, and I see you embracing their compulsive erasure from existence of "type B".
The issue of productivity is difficult, if you think there is a right answer. If someone can work, at incredible cost, should they not take pride? Yeah, it's luck that I, or anyone, can work, but you wouldn't sneer at someone with an intellectual disability that was bagging groceries, would you?