Related to above and some previous posts discussion. Some have suggested you got to be a doctor to discuss/understand these issue. Well its worth pointing out that most doctors aren't trained in these issues, most are dealing more with black and white issue of what do I prescribe for conditions not probabilities and statistics. There are some, we had a pediatrician who had been in research prior and knew we were in research gave us the research perspective of options for our kids' treatment etc.
Now related to the whole covid thing. Why did we not require everyone to wear an N95 masks from the start? Because this was as much an economic (allocation of scarce resources among competing ends) issue as pure medical. We didn't have enough N95 and didn't want a run on N95s. There was a controlled research study in another country of mask use, can't remember country and think it was a standard like N95. The study did find mask use statistically significant vs no but it made very little difference and this was a case where they were trained to wear them properly.
But back to above, Dr. Bhattacharya was a voice of reason and using research for such in the early period, plus he was basing his discussion etc from finding in his and other's current controlled research and statistics. Like said this was an medical and economic problem. Dr. B is trained in economics, statistics and medicine. But there were others also. Many that were concerned about the economic cost of lockdowns and the medical, suicide etc implications of lockdowns and mandates. As said earlier, there were controlled studies as well as other research showing that masks weren't effective for masses even if worn properly, but could be useful for vulnerable if worn properly. Can't tell you how many folks (prob ~1/3rd) showed up in a car to a business that required mask, there mask was pulled down on their chin meaning droplets were on outside of mask, entering store they pulled the mask up which then meant that when exhaling the droplets would be pushed off the outside of their mask. In these cases its possible masks were worse. And there were studies which showed certain types of masks were worse that no mask. But again the N95 was an economic problem.