We want this website to be for patients and not get diluted and confusing with new non-patient members
Yep, that is the reason. Patients who suspect that they might have ME/CFS but aren't sure and don't have a formal diagnosis are welcome to explore it with members. What we are trying to avoid is people joining who may be perfectly healthy except for some relatively minor problem that has been discussed here by members who have that problem as part of their ME/CFS. The same approaches to the problem are not likely to work. Or, people who clearly have an unrelated disease but saw an intriguing post that they want to discuss. Again, discussing symptoms and treatments could lead to confusion--apples and oranges trying to discuss the best climate to thrive in!