He doesn't give the answer I saw in the comments section somewhere in the NYT: Everybody suddenly gets a craving for French toast.
Storms can of course wreak awful damage, but for most people they are a harmless annoyance and perhaps even an excuse to stay inside—a culture-wide justification for renouncing FOMO for a day. To stock up on cozy foods like milk and eggs is to clearly demarcate the storm as a time to put on sweatpants and not go anywhere. Buying a bunch of canned foods—a more practical choice—is decidedly less cozy, and may even carry unwanted survivalist overtones.FOMO — fear of missing out — becomes JOMO — joy of missing out.
Pinsker observes that bread is a very sensible choice. It doesn't need refrigeration, and there's concern about losing electricity. It's the milk and the eggs that are impractical and therefore deeply psychic. To say that is to make the motivation obvious. Pinsker doesn't say it, so I will: You're all running to Mother.
By the way, all the shelter-in-place news about a snowstorm looks pretty silly from my vantage point in Wisconsin. Yeah, I can see why the authorities don't want people out in cars slipping and skidding and getting stuck, and I'm sure the local drivers lack experience driving properly in snow, but the drama is absurd. I watched a little video at the NYT of a reporter wearing a GoPro-type camera and riding a bicycle through Washington DC to show us how terrible things were, and the street didn't even have a light coating of snow. It was wet and black. The man was using the word "blizzard" and commenting about the lack of visibility of the Capitol building in the distance, but there was no problem seeing his immediate surroundings. It was nothing like "whiteout" conditions. (And I've had the experience of driving in whiteout conditions on a mountain road where it was also dangerous to pull over. It was terrifying.)