I guess my point is that what people on the street are wearing for respiratory protection and what I know to be legit respiratory protection from my days at Nuclear Power Stations are two very different things.
You get used to it. I did it for a couple years working at a nuclear power station - not all day every day but you have to wear a respirator and protective clothing in order to access certain contaminated areas. Usually a half-face respirator, but sometimes a full face respirator and on very rare occasions operators entering reactor areas under power have supplied air. As an Engineer I wasn't doing manual labor, though.
Workers wearing respirators at Nuclear Power Stations are performing well rehearsed and planned activities. The procedures and planning book for a 30 minute task is inches thick. The work procedures are quite detailed with pictures and video. For every mechanic entering a radiation area there are probably four staff support personnel outside providing planning and organization. All the tools are laid out and organized in carts. There's a Radiation Protection Tech there taking measurements and air samples. Nobody's just loitering around, they are in and out in a hurry. Then a Quality Control expert will check the mechanic's work and test the work item. Then a Quality Assurance expert will check QC's work.
I called BS initially having seen the size of corona virus against the gaps of high thread count cotton. I theorized however that the air disturbance was enough to create a small virulent cloud around the user and not spread it much further. It appears that's where the science lies....the virus still leaks, but it just doesn't get pushed out as far. The numbers don't seem to lie, even w/shitty face coverings.