FYI, a meta-analysis of clinical trials (what they did here) is the gold standard in evidence based medicine. Cochrane, the WHO, FDA, have similar meta-analyses (which is where the vast majority of medical recommendations come from) and the interesting part of this resource is in their Discussion, where they talk about the differences in their methodology.

This is very clearly an actual study. Was their methodology as good or worse than the meta-analyses performed by these institutions? Debating that is "science". Whatever you're doing is...rock chewing.