It's a reflection of the idea that if civilisation collapses to the point you can't obtain food except by pulling it out of your emergency store a year later, you're probably going to have died of disease, injury, thirst, violence or a number of more pressing concerns.

Seriously, if the ability to get food to people has been down for a full year, you won't have medicine. You almost certainly won't have fuel, electricity, public order, sanitation, or clean water.