I find this thread interesting from the point of view of that historical group of people with very real health problems who grouped themselves (in some cases) or were grouped by some Drs under a label which was disbelieved & stigmatised, and still is. I.e. Me/cfs. And now we're talking about an overlapping group of people with very real health problems & judging the labels that they use to try to describe their v. real experiences in order to organise and help themselves.
The difference though is that the label ME/CFS makes no claims about cause or treatment, whereas other labels such as MCAS do. It's a bit like if we decided that we actually had a disease: 'Microclots Everywhere'. There is a possibility (increasingly remote) that microclots are the cause of our problems, but the claim is not sufficiently well evidenced to be labelling patients with it, or to be prescribing blood thinners for everyone.
I don't think there is widespread negative judgement about people who say that microclots (or collagen problems or haywire mast cells) are the cause of their symptoms. Very few of us have not thought that some idea or other probably was the cause of our symptoms at some point in our illness, only to realise later that it probably wasn't. It's the setting in stone of an etiology in the form of a disease label that is the problem.
Judging a causal hypothesis and finding it wanting should not be the same as judging a person. But, a label like MCAS makes those two things uncomfortably similar.
Having a holding label of ME/CFS that makes no clams of etiology makes it much easier for me move from being keen about one idea about a cause to another. It makes it easier for clinicians to too, and researchers and advocacy groups, to not get stuck in a silo, to not have blinkers on about what the biology is and what treatments work. I liked
@StellariaGraminea's idea about holding labels lightly, but, I think labels that claim unwarranted certainty about a cause are unhelpful in many ways and are very difficult to hold lightly.
I think there are things we, as people with ME/CFS, can do that would make things better for people with ME/CFS. I don't think it is patient-blaming or victim-blaming to say that. It's reasonable to call for our advocates and advocacy organisations to be better. Saying that is not the same as saying that it is our fault that things are so bad, in just the same way that past calls for civil rights groups to work more effectively were not saying that racism is ok.
Nightsong expressed things extremely well in the post above that included this manifesto for change in our advocacy groups:
What is most urgently needed is for charities, prominent advocates & advocacy organisations to be sensible. Don't associate with fringe practitioners; don't join "overlapping illness" alliances; don't promote tenuous links to disputed conditions; avoid taking on as advocates people who likely have conditions other than ME/CFS; don't hype trivial or non-credible research; advocate for supportive medical care, not BPSery or unproven drug therapies. In short, present as sane, sober, and sensible interlocutors.
There are things we as people with ME/CFS can do ourselves too. We can get involved in our charities if we have the capacity, we can elect sensible trustees. We can call out charities that don't present themselves as professional credible organisations. We can reward good organisations with our donations.