> If it turns out that ME/CFS doesn't has a physical marker, then what?
The problem is that ME/CFS is similar in presentation to other conditions such as for example certain kinds of depression. The difference is that exercise is thought to help with those conditions and exacerbates ME/CFS. Thus there are two different groups of people, one who you are helping by encouraging them to exercise and one who you are harming. If you can't tell them apart the system is bound to hurt someone.
The problem is that ME/CFS is similar in presentation to other conditions such as for example certain kinds of depression. The difference is that exercise is thought to help with those conditions and exacerbates ME/CFS. Thus there are two different groups of people, one who you are helping by encouraging them to exercise and one who you are harming. If you can't tell them apart the system is bound to hurt someone.