Normal (i.e. non-sick) people don't need masks, this is good advice. As a matter of fact buying masks is actively harmful, because you are depriving people who do need them (the sick and their caregivers).
If the US had a proper supply of masks, it would certainly be nicer to see them wearing them, though. But you're correct that given how terrible the supply seems to be, it might be the best thing to say.
Normal (i.e. non-sick) people don't need masks, this is good advice. As a matter of fact buying masks is actively harmful, because you are depriving people who do need them (the sick and their caregivers).
Source: https://www.cdc.gov/coronavirus/2019-ncov/prepare/prevention...
(No comment on the rest of the tweets though)