Where has anyone said they have? Ive not seen the OP say this was an emergency or anything like that so where are people getting this is an emergency?
But as you have quite rightly pointed out not everyone has an excess of funds, this may be one of many reasons. They may have a few days excess but this weather is due to be this hot until the weekend.
And as for get non perishables so you can just walk to the shop, its a crazy idea but not every option works for everyone. Ive just had surgery, I cannot drive and I cannot walk to a shop, in fact it would take over an hour to walk to a shop from mine for a healthy person but even without surgery I would need a wheelchair and I live on country lanes where using a wheelchair or mobility scooter just isnt possible. I dont live closer to accessible things because the cost to live closer is not affordable. I have non perishable foods in but they dont last indefinitely if I need to rely on those for all the just in case times.
So the snidey comment that person made, as thats the only type of comment they seem to add to these discussions, was bizarre and irrelevant because in order to stock up you need to shop.
So how much foresight are people required to have to satisfy such posters seeing as the weather is at its peak heat in a couple days time so they may well have been trying to shop before those peak heat days? How much excess are they required to accommodate to be satisfactory to people that just want to find an issue with no matter what people do? Not everyone lives close by to just nip to a shop, not everyone is fit and able and some people use the services available to them. Not everyone can afford to have weeks of excess food in on the off chance that things go wrong. Do you not get that some people may have different circumstances to you?