In some of these cases, the researchers have not explicitly stated a hypothesis, but rather have more broadly found evidence of odd things occurring in patients with ME/CFS. For instance, I think the immune patterns found by Columbia are more in the realm of "biomarkers" of some unknown process related to the disease rather than a theory of what is causing the disease itself. These are still important findings, since the underlying disease mechanism remains so elusive.
Likewise, Fluge and Mella, have been very circumspect about whether their findings suggest antibodies, autoanitbodies or some other process that is somehow being moderated by Rituximab.
There's also a difference between having a compelling hypothesis and having compelling evidence for that hypothesis.