SiliconWizard, I may be stubborn but at least I don't hand wave and pretend to know better than the authority on the matter. Do you really think your arguments haven't occurred to an institute's worth of health care professionals?
You didn't address any of what I just said above.
I linked to the recommendations of the WHO that clearly imply that masks are to be used if you may be infected, or if you're dealing with someone who is. The WHO you keep mentioning writes that. Have you actually read what they say?
The only thing I'm questioning at this point concerning what they say is that they seem to restrict the use of masks only if you or someone you have to be close to is infected, and my questioning is because there are likely a lot of people not showing any symptom but that are also clear potential vectors.
I do not agree again that only if you cough or sneeze heavily you're a hazard. We keep emitting very small droplets all the time without noticing it. And anyway, we may just cough or sneeze randomly without being able to control it just because of dust or anything else. So my point is NO you don't have to have developed clear symptoms to be contagious.
Now given the scarcity of masks, it can make sense to be cautious about promoting them unreasonably. This is risk and resource management. I personally think that if they had recommended for everyone to wear masks regardless of their condition, this would have triggered an uncontrollable panic as we just can't provide them. That I understand fully. I also agree with the point that most people don't know how to put them on properly, but still think some barrier is better than none at all.
For the rest, I again haven't seen in the WHO recommendations a clear point saying that masks are useless, since they recommend using them in the above cases.