The point is that some retired professor in microbiology takes a little lamplight making claims about covid, which unfortunately are factually utterly and despe

The point is that some retired professor in microbiology takes a little lamplight making claims about covid, which unfortunately are factually utterly and desperately wrong. Now people refer to him expert in a facebook thread. That's the "appeal to authority" fallacy, which you could call out. Extensive use of fallacies is in the active repertoire of demagogues. That's why it helps to study them, a bit, so you recognize a skunk if you meet it in the wild.