That diabetes rate around 20% strikes me as high. I did a quick google search that suggested population frequency around 7%, but maybe it's simply a reflection that ME/CFS patients are more likely to visit a doctor if they have concerns about a co-morbidity like diabetes as well, rather than if they don't. And age group might be significant too.
The 71% co-morbidities rate makes it look like ME patients are going because they have other things. I never spoke with my GP about treating my ME - we just agreed that medicine does not have all the answers yet. (He retired and I was forced to explain my illness to his replacement who was sympathetic enough but had nothing to offer) However over the years I have been treated for other things. In particular I attend a diabetes clinic with a nurse practitioner every 3 months. The regular blood tests for my diabetes give me the sort of regular examination everyone with ME should get but without that other disease I would never see a doctor. Why bother when it is difficult and you know nothing will come of it.
The lack of health care for pwME negatively affects some carers' attitudes about health professions. In some cases, so much so that carers avoid engagement with health professions for varying medical needs of their own.