[kansface]

Obviously, the material a mask is made from stops medium sized particles from flowing through some highish percentage of the time. No good faith actor is disputing that. Studies don't control for real world usage, actual public adoption, actual masks, etc. They also do not control for changes in behavior that we'd expect to occur contemporaneously to the time periods mask mandates are adopted (ie, during spikes in infection). When infections go up, I personally stop going places where lots of people congregate - a huge percentage of people change their behavior in ways that are both germane and impossible to track in response to perceived risk. They also do not or can not control for the differences in behavior in the societies that can actually adopt and enforce mask mandates in the first place; ie, a city that refuses a mandate in the face of a spike has citizens that are more risk tolerate (or something) as compared to eg SF.