i'm not saying that CFS is "fake", or that ulcers, fibromyalgia, or migraines are "fake." to say that you can "will" these away is an infantilization of psychoanalysis. i would never classify CFS as "laziness." (although i will note that the DSM has historically had no problem about enforcing moral judgements like this in its taxonomy.) people take "psychosomatic" to be synonymous with "it's all in your head," when the point is that it is precisely not "all in your head."

i very much agree with you that part of this discussion is about the questionable validity and reproducibility of the official diagnostic categories. what i disagree with you about is that anything could be exclusively either physical or psychiatric. that's obviously false.