Also checked the second link, it says:
There is some evidence to support the wearing of masks or respirators during illness to protect others, and public health emphasis on mask wearing during illness may help to reduce influenza virus transmission.
Not very convincingly concludes the opposite of the claim.
Covid is spread mainly by respiratory droplets, masks act to catch those droplets at source, it's simple logic.
Whilst only a properly fitted P3/N99 mask gives absolute protection from infection via inhalation, community mask use is an important pandemic control measure to keep the reproduction rate 'r0' to a minimum.
That the advice from WHO and some governments has been muddled, illogical and inconsistent does not detract from the truth.