And I'm as disappointed as you in some of the comments from US health authorities recently, although I'm not convinced that the kind of separation of 'ME' from 'CFS' that you're hoping for is a realistic goal until we have clear scientific evidence that such a separation is justified, indicating exactly where the line should be drawn (e.g. a biomarker to distinguish a subset, and high quality evidence indicating why this does represent a distinct disease).
Sorry to be so long replying to this. I just wanted to point out that the IOM examined the different case definitions and definitively said that "a diagnosis of CFS is not equivalent to a diagnosis of ME." Given what we know about PEM as a symptom and the distinctive underlying biological pathology in energy production demonstrated by CPET, I think the IOM's statement does has scientific evidence to back it up.
That's not to say that there are not subsets inside of ME. I am sure there are. But the heterogeneity of CFS is man-made, encompassing unrelated conditions. P2P called for Oxford to be retired and IOM dismissed Empirical for including PTSD and depressed patients. What's left is Fukuda but only 20% of the unique combinations of Fukuda symptoms require PEM so what else is in there. So I think there's plenty of evidence to separate those who meet only CFS definitions from those who meet definitions that require PEM