But we also need to use our brain.
Even when trying to use my brain, I have troubles understanding how droplets can distinguish the direction of passing through a face mask, i.e., how my face mask can help protect others from my droplets, but how it cannot protect me from other people's droplets.
Well, I do understand that if the holes are too large, it will not be a 100% protection, but I do not really understand how the direction would matter.
That said, preventing a run on masks is important if you don't have enough, because some people need masks more urgently than others. I am convinved that in order to prevent a run on masks, you cannot just tell people the truth, but you need to lie to them, because many (or most) people will still get a mask if they know it is actually somewhat helpful.