That's not what this is saying... Its just extrapolating the upper and lower bounds of the study's statistical data into real world terms. That highlighted quote is an extrapolation of the upper bound. If you look at the upper and lower bound together, it is more likely that there is a small benefit towards a reduction in viral transmittance in wearing a mask.

That does not mean this promotes mask wearing. on the contrary it does the opposite. Even in the best case scenario of a 20% reduction of viral transmission, that is still meaningless on the population level, and in fact promotes bad behavior from at risk populations due to a false sense of security.

That doesn't even touch on the increased probability of pneumonia (the real cause of death in this plandemic) from wearing the types of masks most people wear.