On top of the patient-blaming concerns, I also think it's likely just impossible to stop advocates publishing stuff about MCAS/hEDS/etc, at least until science advances on this and has something useful to offer. For now, these labels are very important to a lot of people, not to mention totally entrenched on social media.
Like others, I am also skeptical doctors would take us much more seriously even if we could ditch the extra labels. We're already committing a major sin in appearing healthy while claiming illness. Like I think
@hotblack is saying, the woo-beliefs seem more likely to give doctors an easy out (because it suggests the patient is being difficult to work with) than to actually be the deciding factor, perhaps on a subconscious level. Not arguing Jonathan's specific case though, people are idiosyncratic, and his situation sounds special, this is just a general statement based on how many of these interactions go as patients.
That all said... Of all the groups involved, doctors and patients seem the two hardest for us to convince directly. Conversely, getting outside people with power involved seems to have had a really positive effect on our position (thinking of DecodeME, and all the other great researchers here on S4ME, journalists like George Monbiot and David Tuller, there was a good SciShow episode as well on ME/CFS and so on). Improving the broader cultural view, and even the scientific view, on ME/CFS honestly seems more tractable than convincing doctors and patients, because journalists and scientists have less of a personal stake in the fight. And then when the culture and science shifts, patients and doctors come along for the ride.
On that note,
@Jonathan Edwards, I think you mentioned earlier in the thread that scientists were easier to bring over than doctors. How can we recruit more scientists?