Better late than never, but they'll need to put some work into countering all the anti-mask propaganda that's been flying around for weeks now.
There has been tons of rhetoric designed to discourage the public from buying masks that gives the impression that public wearing masks won't help. A lot of headlines to that effect that lack any nuance at all.
AFAIU, some populations are more likely to exhibit non-overweight, non-obese NAFLD. Likewise for type 2 diabetes.
Personally, I have been using these cheap masks for over a decade whenever I have to clean any dusty place like a garage. If I don't wear one, I am almost guaranteed a a bad allergic reaction. If I do wear one while cleaning, I might sneeze a bit but usually not need Benadryl and pass out for rest of the day.
I imagine same principle applies when it comes to COVID19.
What is the mechanism for this?
At first, I'd expect it to be the other way around--if I'm wearing a mask and cough the mask is going to bear the full force of my cough. All of the cough is hitting the mask, and the cough is moving at its fastest speed.
If I'm not wearing a mask and you are, my cough is going to be spread out some when it reaches you and slowed by air resistance, so your mask should only have to deal with a fraction of my cough and at lower velocity.
Thus, I'd expect your mask to have a much easier task than mine.
Is it that the drops of moisture (and phlegm and whatever else might be in a cough) are bigger at the point of emission and break apart as they disperse, and so they have a harder time going through a mask at my end than at your end?
If that is the case, I still have to wonder what happens on subsequent coughs. I cough, producing big drops that the mask stops. Still, the viruses in the drops have to go somewhere when the mask absorbs the droplets, right? Does my mask end up moistened with virus-contaminated water? Will my subsequent coughs as they blast air through the mask then be able to knock small virus laden droplets off my mask?
Certainly masks will help to some degree, as they will filter out some particles and protect you if someone directly coughs into the mask, but I don't think they are effective compared to things like hand washing.
I am not a doctor, not medical advice.
It's often helpful to evaluate conspiracy theories using Occam's Razor. What's the simplest explanation which fits the facts?
As masks are produced in massive volume then yes encourage everyone wear one as directed.
Where I live, we have a long way to go to perfectly implement social distancing. Given the severity of the pandemic, anything to help stop the spread should be considered and implemented.
Ultimately we need to change our nature, but that's most likely off topic here.