You offer a valid observation.
This may not be clinically accurate, but I don't see "treatment-resistant" as being a secondary condition, though.

Participation here certainly is dependent upon how I'm doing and where I am in my understanding of my condition.
I joined years ago when seeking coping strategies and perspective after stumbling along on my own for several years before that.
Then I disappeared... not doing tons better, probably more in denial.
Now, my life seems to be falling apart. Meds haven't worked; TMS hasn't worked.
ECT isn't proving as effective as I'd hoped, even.
...so I'm here trying to figure out what I need to ask to properly convey what I need.

In short, I think my own behavior illustrates your observation.
I don't think, however, anything is invalidated by the limits of our population/members.