I'm surprised at the naivety of some people. What we saw in March was a mild disruption to the usual supply/demand ratio, which had a huge impact on the availability of goods. Supermarkets round here had no fresh fruit or vegetables after 8am each day. No toilet paper, no pasta, no fresh meat (except Waitrose, who had venison). No tinned food. Freezers decimated. Cleaning products gone.
What on earth would happen if there was major disruption? Not necessarily a SHTF scenario, but something to prevent deliveries for a few days or weeks. You can't assume that shops will cope, that they will even be open.
Making planned extra purchases, a few extra items on top of your normal shopping each week, is responsible and is common sense. It's no different to the behaviour humans displayed for centuries: in the autumn you salt meat and preserve what you can to tide you through the winter when fresh food will be scarce. Stockpiling, even "hoarding", are not the same as "panic-buying". In March the stockpilers and "hoarders" weren't the people queuing outside of supermarkets for an hour each morning, they were safely at home.
Ignoring the current circumstances, it is worthwhile keeping a month or so of food in your home at all times. You might suddenly lose your job and having the food will help take some of the pressure off. In these times it's even more sensible, because you could be ordered to isolate at any moment.