Corporations are doing it because they want their employees and customers to feel and be safe. The government’s not enforcing anything - the market is.
I don’t think so. I don’t think business want to be forced to choose between one half of their customers and the other. But they are forced to, just as we are all forced to wear the useless masks, practice the useless “social distancing”, and deal with all of the other nonsense, for a lie. The reality is that if business actually felt free to require or not require masks and the distancing and the incredibly stupid floating plexiglas everywhere, you’d have some business that would go one way, and some that would go the other (and the few that have tried to go the other way, have been immediately hammered by the government). So almost all businesses go with what the state wants, because they don’t want to be fined or shut down, and because they know the government will support anyone who sues a “non-compliant” business, claimIng that they caught the super scary ultra deadly COVID in that place of business.