Here's my pet theory: It's mostly about preserving companies' brands and not associating them with the crisis. Someone wearing a face mask is a very visible (literally in-your-face) expression of the pandemic. Companies don't want this associated with their various brands. Especially a service worker working directly with the public. [Company] fears that if the public starts seeing [Company] workers wearing masks, they'll associate [Company] with sickness. Remember the thread yesterday about hospitals. The health care workers that were willing to post anonymously suggested that their lack of protective gear was more about bad PR and image than a lack of supplies.
This is just like companies not wanting their ads to show up alongside porn or hate videos. They're trying to avoid a bad brand association. No company wants the public to see face masks all over their brand.