You are being rather obtuse. That “leap” is the main point of the paper, stated in the
abstract:
This paper is (casually) cited not for its content on masks, but for its attention to second-order factors.
These are utterly ignored in our pandemic response. It is possible that masks, through their primary, overt mechanism, inhibit the spread of disease. (Intuitively.
It’s complicated.) It is also possible that the perfunctory, 2-week old masks sitting in car door sills are an unintended, covert risk to health, not to mention other aspects of existence. What is most evident is the shocking inability to openly, rigorously account for both costs and benefits of mandatory public health measures.