As above OP, in the vast majority of cases it is because they are total dicks.
I live with someone working in food stores/retail. The staff are bending over backwards endangering themselves and their families to get people their food, for very little pay and who no real enforcement of safety measures- no masks or gloves sent down, no signs. Everything that have had to get themselves.
Customers are still out for just the morning paper, or a chocolate bar or a lottery ticket or a few bits and bobs that they fancy such as making a nice cake to cheer us all up. Absolutely isn't essential shopping and the shops are being treated as though they are a jolly escape from this for the bored and entitled.
People should be deeply ashamed. Go to the shops only if you need MEDICINE or FOOD (if you literally have none at home NOT because you fancy something specific or want to bloody treat yourself). Stop trying to pay with cash, stop giving workers grief when you are asked to leave because you were not capable of understanding that coming in several times a day is not allowed, nor is popping in for one non essential item. Treat it as though it is dangerous to do, because it IS, and treat it as though it is a place you will only go of you have to.
I am immune compromised, have a serious illness and a separate heart condition. This person is my carer outside of this job and they have no choice but to work (including overtime to meet demand) unlike a lot of people at home, safe, with pay. I wouldn't survive without them and likely won't when they bring it home. Galling to have to have extra worry about that because people are oxygen thieves.