Its interesting to note that you didn't include the date on your document. That would have shown that it was March 2020 , well before more information became available and recommendations by WHO and others that mask wearing was beneficial.
In June WHO issued the following guidelines.
"To develop the guidance, the agency consulted with a range of international experts from different countries and disciplines such as infectious diseases and epidemiology. Their review of a variety of evidence demonstrated some new findings, including that face protections, including respirators or medical masks, can result in a large reduction of transmission of coronaviruses, including COVID-19.
Recommendations, such as those regarding fabric masks, are the result of new research that the WHO commissioned that was not available a month ago. This new evidence, said Dr Maria Van Kerkhove, WHO Technical Lead, has shown that the recommended fabric combination "can actually provide a mechanistic barrier that if someone were infected with COVID-19, you can prevent those droplets from going through and infecting someone."
Officials acknowledged that in some countries with dense populations it is difficult, if not impossible, to maintain social distancing, making masks "very important," stressed Soumya Swaminathan, WHO Chief Scientist, and meaning that offices, transport agencies and schools will need to examine their recommendations closely as countries lift lockdown restrictions. "Every organization, industry and sector needs to think about what are the measures that need to be put in place," said Swaminathan."
Given that a large number of infected people are asymptomatic it is prudent that all people wear masks if you are trying to eliminate transmission of the virus.
