If it’s airborne, then a surgical mask or random piece of dirty cloth will not be effective.Not questioning knowledge of filtration at all! For the first few weeks after Jan 1 2020 the prevailing knowledge was that covid-19 wasn't airborne. hence the advice at that time was that masks were unnecessary. They learned more about it as time passed and are still learning. That is how science works
If it’s carried in aerosolized droplets (sneeze/coughing), then there may be some benefit.
If the presumption is it’s airborne, the guidance is backwards.
There are numerous peer reviewed studies that demonstrate the general effectiveness of mask use among the general population. The guidance until now has ALWAYS been to recommend against, but somehow THIS virus is magically different.
The mask requirements are NOT based on good science.