I think in general Paul Stamets is not a scientist per se in the form of writing papers and doing academic research but it is hard to deny his influence as a popularizer of mycology. He also writes about the study and growing of mushrooms and these include the edible not just the psychoactive kind. I know he has done some bioremediation demonstrations but perhaps according to the poster these weren't performed with enough scientific rigor. Not everyone who studies and shares information about something does so from the confines of the traditional academic background and not everyone needs a PhD to be an expert about something so perhaps that is why some people are down voting.