You are more likely to get wafts of unpleasant body odours from a overweight sweaty geezer who’s taken his shirt off because he’s too hot than one who keeps his shirt on.
Stop moaning and put a shirt on if you want to stand near to people who are doing their food shopping. A bit like parking your car, taking reusable carrier bags, and having the means to pay for your items, it’s all part of the shopping experience which most people manage perfectly well in accomplishing without any sort of problem. So there’s no need for anyone to be that precious or attention-seeking.
And it’s got nothing to do with being middle-class, even working-class people can afford shirts.