Nobody is rejecting n=1 anecdotal evidence out of hand. What is being rejected is that such evidence is a sufficient basis for recommending any treatment to other patients, without robust clinical trials. Particularly from the safety angle.If you were to reject n=1 you would reject a whole lot of things in ME/CFS - including some that turned out to be helpful. In a disease where treatment trials are rare and don't even scratch the surface of what is possible - you have to start somewhere.
There is no short cut to good evidence, and effective and safe treatments.
If the whole ME saga has taught us anything, it is that much.