I was pretty sure that I remember a surgeon telling me, during my long hours of accidental surgical training, that masks don't protect the patient during surgery: 'Why then,' he asked rhetorically,' do we wear them?' Well, to protect the surgeon from any pus, blood or other detritus that may fly into their face. I've refrained from bringing this little oyster of knowledge up during this bout of medical malpractice, but when a colleague photoshopped a mask onto his profile picture I had to say something. And, unlike 97.4% of doctors, I actually research shit. Below is the study showing masks are NOT recommended for use in theatre by surgical staff. So if they won't even protect a patient from a halitotic surgeon billowing bacteria into an open wound, why would you think they will work in the general population?
As a review of mask use in surgery states:
Masks have been associated with more infection, not less, as the mask itself acts as a nice, warm, incubator for bacteria and viruses.
As I've said before, recommending masks is probably just an epigenetic throwback that doctors have; a subconscious psychological fragment from a time when they knew even less than now.