I am genuine in asking why you consider this to be nonsense.
It is a long story, hidden in the threads, but in brief.
I was involved in the hypermobility story early on in 1978 when Rodney Grahame set up a clinic at Guy's Hospital in London. It was my research base. We wrote a paper on cardiac involvement that didn't really make sense. I was too junior at the time to say so. Since then I have seen the hypermobility bandwagon grow but never seen any convincing data that there is a 'disease' or 'illness' based on common polygenic 'hypermobility' - which in practice just means the people who are a bit bendier than average. After leaving Guy's I decided to keep clear of the subject. Around 2000 I was asked if I would take over Dr Grahame's clinic when he retired but declined!
'hEDS' replaced 'EDS III' as a term for hypermobility without internal organ problems. It is inappropriate because EDS is defined as a monogenic disease - caused by one connective tissue protein gene being defective. Hardly any 'hEDS' cases have been shown to be due to a single defective gene. The term is used to cover anything from 1 in 5000 of the population to 1 in 5, so is too ill defined to be any use anyway. (In other words some doctors will diagnose it a hundred times more often than others, for no good reason.)
Lots of children are bendy and can do party tricks - about one in five girls and one in ten boys. It is very normal.
The idea that hypermobility (or EDS) is associated with fatigue seems to have been started off by Peter Rowe around 2000. A supposed association with general pain goes back to 1970 or so. The fatigue story was raised again by the biopsychosocial enthusiast Hans Koop in I think 2009. It got into the folklore. However, inasmuch as there are any reliable studies they show little or no association. The UK ME Biobank did not pick up hypermobility. Some large studies of children failed to show anything much (I think in Scandinavia) - not even a link with pain much.
I was close to all this much of my career, since Dr Grahame moved to UCL, where I was, and a number of our clinical trainees worked in his clinic (which I decided not to take over). Over the years I heard endless claims about links with pain and dysautonomia and fatigue but never saw any data. Having taken an interest in ME in retirement I looked again and there doesn't seem to be any - beyond a few case reports that are almost certainly related to clinic attendance bias.
There is absolutely no reason that I know of for hypermobility being associated with ME. Stories about neck subluxation and vascular compression appear to be baseless. Unfortunately there are a good number of doctors and therapists, particularly private physicians who sell HSD or hEDS as an explanation for just about anything. Even in mainstream rheumatology it is common for doctors to check for hypermobility and then blame whatever the person's symptoms are on it - it sounds knowledgeable but has no basis.
A very small number of children have major laxity problems with certain joints - often just one pair - knees or shoulders for instance. Subluxation and gait problems can occur. I used to see people like this about once in ten years. They have very real problems with that specific joint but otherwise tend to be quite normal.
