There was decent evidence that both medical masks and N95s were effective against SARS-1 in a medical setting, and some weakish evidence that they worked in a c

There was decent evidence that both medical masks and N95s were effective against SARS-1 in a medical setting, and some weakish evidence that they worked in a community setting. There was really no good reason to believe that they wouldn't work to some degree for the general public. Concerns about the lack of fit testing could have been mostly alleviated by instructing people on the importance of and how to perform a pressure check themselves. The original concern seemed to be about supply, as people were specifically instructed not to buy N95s. Of course, that didn't stop the Chinese government and Chinese aid groups from buying essentially everything in the supply chain and shipping it to Wuhan. If supply concerns were the real issue, it's difficult to understand how this was allowed to happen, but the government was making a lot of mistakes back then.