A literature review looking at severe fatigue in cancer patients also noted that counseling and exercise can be helpful in cancer patients. Using the line of reasoning applied by some to the Pace study, this would also suggest that cancer is all in people's minds.
Of course, this is simply an absurdity that points to the simple fact that for most severe debilitating diseases, emotional support and coping skills can be helpful along with maintaining conditioning. In chronic fatigue syndrome, people are facing an energy crisis so they can only walk or exercise to a certain point, beyond which they crash and burn - so you only want to exercise "as able." This means listening to your body and seeing what feels comfortable. On the other hand, if you don't exercise at all, your body has a "use it or lose it" approach to efficiency, and you'll decondition.
Basic common sense says that for cancer, chronic fatigue syndrome, multiple sclerosis (which doctors also used to believe was all in people's minds, calling it "hysterical paralysis") and any severe disease, it is helpful to get emotional support, coping skills, and exercise as able. The problem occurs when a form of cognitive behavioral therapy is used that includes beating people over the head with the misguided belief that the illness is not real. This then changes from teaching coping skills to being abusive.
It is a basic matter of common sense. CFS is real and it is treatable.