Nor should we. We don't have a federal mandate on red meat consumption, soda consumption, tobacco use, hours spent in front of a screen, being overweight, developing type 2 diabetes, engaging in unprotected sex with strangers, kissing, high-fiving, or using ladders.We have no federal standards for masks, or anything else. The entire narrative from Republicans as long as I can remember, and increasingly Democrats, since Clinton, is that the government, other than the military, is bad, inefficient, and corrupt. And that only private companies can be trusted to do anything. Both parties have done their best to prove the truth of that view with admirable success.
How could the federal government possibly have authority on mask use when Covid ranks 10th on the list of things that reduce life expectancy? They'd have to have worked through the other 9 things first before getting to mask mandates.
I'll steel man this by pointing out that mask wearing is meant primarily as a way to mitigate spread to others. Those other people have a choice to be in public. They also have a choice to visit establishments that require mask wearing or not. One can no further argue that that wearing a mask should be mandatory than protected sex (or monogamy) should be mandatory. Both affect community spread of disease.
It doesn't matter if a federal mandate can prolong my doomed life; that's my job, not theirs.
It's proper if local government wants to mandate it because that's the role of local government. We're free to elect other officials or move if we don't like it. If government authority were delegated properly (as intended), we'd care who is POTUS as much as we care if Taylor Swift releases another country album.