Here is a link to the document you quote:
https://www.hill.af.mil/Portals/58/documents/Corona Virus/ClothMasks.pdf
It also contains the statement:
"Data regarding the “real-world” effectiveness of community masking are limited to observational and epidemiological studies." This is because these kinds of masks were not designed for, nor are they capable of blocking particles of the size of viruses, or even small droplets with many thousands of viruses, and every attempt to tests the physical function of them shows they cannot work. Surgical masks were intended to keep spittle and flem from getting in the wound, and N95 and similar masks were intended to keep the wearer from breathing IN particles, where the interior of the mask is at reduced pressure which helps to seal them to your face. When exhaling the air just blows around them - try it with a cigarette. Some of them even have valves to prevent your exhalation from blowing into your glasses, etc.
So they avoided that issue by including that qualification, which essentially says "it looks like they worked anyway", but that hardly accounts for a multitude of other factors. It's not something that could ever pass peer review, and the document a blatant attempt at an appeal to authority - they're trying to look authoritative when the conclusion is not at all proven.