There's stockpiling in case of the apocalypse (who knew Brexit would turn out like this?!).
And then there's a general "keeping the cupboard well stocked" which might mean having slightly more than normal but really only enough to put together a variety of meals without having to shop (or shop for very little) for a couple of weeks. So if there was a short term delivery issue, you are ok because you have things at home.
Just like if it snows, you are ok and don't need to drive/slide/slip/sledge to the shops.
Just like if it gets very stormy and you want to hunker down for a few days.
Just like over Christmas and you want to enjoy time with family and not go shopping.
Or just like when life gets crazy and you know you physically can't get to shops for a proper shop for a couple of weeks so only want to be running for bread and milk in the corner shop next to the train station - or is that just our house?
Sometimes, people who "stockpile" are people who bulk-buy the things they normally use when they are on special offer.
Or they make a concerted effort ahead of some big event to make sure that's one less thing to have to worry or even think about.
It doesn't necessarily mean hoarding cellar loads like you see on (Extreme Coupon programmes and similar) tv - just having cupboards that are reasonably well filled with things that you know your family will eat and that will make life easier for you.
Having grown up in the countryside where occasionally snow did impact us, and where "food shopping" for our large family meant a big trip to the city 25 miles away (main stuff - we used local butcher and milkman and cornershop for bread), so it was a large shop on those trips, I am used to the pantry/cupboards being well stocked.
It means I can go to the cupboards and bake, after dinner on a random Wednesday night, because I have the necessary ingredients. Or change the meal plan because we forgot to defrost the meat planned and need to make a storecupboard meal instead. It doesn't mean eating spam or similar for weeks on end!