no its based on the knowledge that there have been 33 million cases... and as of now...
there is no statistical meaning evidence showing Covid is transmitted via aerosol
no statistical meaningful evidence showing Covid is spread by asymptomatics
Hence, it is not surprising there is no or scant evidence or studies showing masks alone prevent the spread of Covid.
Additionally... being friends with doctors and married to a nurse with masters in community health I have been aware of many the studies quoted in that article. Its not new. Prior to Covid there were all sorts of OSHA requirements. Some requirements designed to protect workers from being harmed by masks and many telling us that surgical masks are unlikely to work in most circumstances....
The evidence of masks not working is all over if you educated yourself.
for instance....
https://www.osha.gov/Publications/OSHA3219.pdf
Surgical masks are not designed or certified to prevent the inhalation of small airborne contaminants. These particles are not visible to the naked eye but may still be capable of causing infection. Surgical masks are not designed to seal tightly against the user’s face. During inhalation, much of the potentially contaminated air can pass through gaps between the face and the surgical mask and not be pulled through the filter material of the mask. Their ability to filter small particles varies significantly based upon the type of material used to make the surgical mask, so they cannot be relied upon to protect workers against airborne infectious agents. Only surgical masks that are cleared by the U.S. Food and Drug Administration to be legally marketed in the United States have been tested for their ability to resist blood and body fluids. How to Contact OSHA