The real point is to give the appearance of having made an effort to enforce social distancing. Corporations are scared to death (no pun intended) of negative press or law suits accusing them of not taking sufficient precautions, and so where they can and where it's obvious they enforce these stupid restrictions. Only allow a certain nbr of shoppers in the store at any one time so that the density is low BUT if idiot individuals want to stand next to each other in the aisles well there's not much they can do about that. People of course see all of these actions and internalize it, leading to moronic behavior at the individual level. As well the FUD (fear uncertainty doubt) factor is large. For example my buddy's a pretty bright guy but we ran an errand the other day and he insisted on wearing his mask in the car. He tried to pass it off as a lark but it's clear that 'fear of the unknown' was driving it. There were lots of other cars with people wearing masks so he's in good company at least.