You're talking about people who have suffered for years with painful illnesses that have seemed impossible to treat, connecting online and working together as they experiment to find possible treatments, testing the results and reporting back so others can benefit from the learnings.
It deserves better than this kind of grunting dismissal.
Sure, much of the evidence around for this stuff is anecdotal or n=1 pathology results, but it's necessarily the case that anecdote and small-sample data is the first step in the chain of events that can lead to scientific findings.
If your point is simply that sometimes people believe things that are untrue, that is obvious to the point of banality.
If it’s that anyone experimenting with carnivore diets and reporting positive results should by-default be treated with distrust or contempt, your point seems to lack both compassion and scientific awareness.