It's disappointing to find out that we don't have "the" answer to ME/CFS. And XMRV was appealing in the sense that a virus is a cause-and-effect that people, including doctors, understand. It would be a clearcut answer to those who think ME/CFS is psychosomatic or malingering. It would probably lead quickly to treatments. On the other hand, I can't be completely disappointed that I don't have a retrovirus. If it's not something contagious spreading through the population, I'm glad. If I haven't inadvertently passed it to loved ones, I'm glad.
I don't think it's a cause for anger, though. It's a shame this has gotten so politicized and ugly, but basically the science worked the way it's supposed to. A team of researchers looked for something and found it, and reported their findings. Discounting those who rushed to discredit those findings like a cat covering dirt, other serious scientists tried to find the same thing. They tested the theory. It didn't work. Other scientists tried to figure out what was going on and presented counter-theories that the original finding was contamination. (Discounting the part where the scientists started slinging insults and innuendos at one another.) The original scientists check their results in a blinded study and don't get the same results. Others of the original scientists test the counter-theories of contamination, and find them true. The knowledge creeps forward, and eventually, one hopes, reaches a consensus of scientific opinion. This is how it is supposed to work, and it is working.
Nothing about this implies the WPI did sloppy work to begin with. Illia Singh took extraordinary precautions against contamination in her study, and still managed to get some. It's very, very difficult work, and it's breaking new ground. They are working with such very low copy numbers.
And it's not all over yet. The preponderance of evidence is mounting against XMRV, but I wouldn't close the door until the Ian Lipkin study results are in.
In the meantime, a number of people who didn't realize that ME/CFS is serious are taking it seriously. We have new research going on. Ian Lipkin is going to be looking for other pathogens, Jose Montoya is looking at HHV-6, John Chia is looking at enteroviruses. We've got people looking at the immune system and the energy physiology. The new ICC criteria should lead to much better studies. We've got several candidates for biomarkers that can be tested with the new criteria. The Lights are hoping to market a test. Things are happening. It's not a time to lose hope.