If EVERYONE stays home, how do stores remain open? Do we think they are run by robots?
I try to use language with some degree of precision. I said "assume no stores will be open during that time". ASSUME, not "stores will definitely be closed during that time". Assume, as a part of planning, not categorically know, because the assumption will make for better planning.
It is far safer to make this assumption and be wrong, than to discover not making the assumption was a mistake.
In the first case you end-up with extra food and supplies you did not need and will simply consume over several months (or donate to the Red Cross, which would be fantastic). In the other case you and your family could suffer greatly due to being utterly unprepared.
Maybe it's my aerospace background...I have learned the hard way that ignoring potential failure modes and corner cases is the mother of all fuck-ups.