I definitely know people who were posting online about how they had 6 months supply of dry and canned goods socked away. A few days makes sense in any case; I actually lost power for 2-3 days this summer just because of a storm. But I could easily cover that with just what I normally have in the house.

To be fair to those people, at the beginning of the pandemic there was a lot of uncertainty around COVID-19 transmission rates. Buying a few weeks of food was a good way to hedge against the potential case where COVID-19 was so virulent that even going to a grocery store presented a high risk of transmission. Of course, we now know that even in a hotspot grocery shopping using basic precautions is fairly safe. But it was not clear at the time.