That's just about true. The original experiment showing that cloth between hamster cages reduced transmission was pretty strong evidence that it ought to work.

That's just about true. The original experiment showing that cloth between hamster cages reduced transmission was pretty strong evidence that it ought to work. And there have been some retrospective studies finding that masking was effective. The Cochrane study just came up with a not- statistically-significant result on their metastudy that included a variety of different pathogens, including COVID-19. The only reason to think that masks are a bad idea is that a lot of people and groups of people of various beliefs, desires, fears, phobias, hopes, etc, can find ways to react that effectively put us on a planet where masks do more harm than good. That's entirely possible, given that most people might prefer to live without the masks if they had a choice.