Another Consideration....
Our economy is interconnected. One small example is oil refining. Oil cannot be simply refined to one thing; it is "cracked" into different components. Well, closures of businesses means that only diesel remains in high demand for trucks, there's very little demand for gasoline since you just told me I can't go take a vacation or drive to work (thus the wholesale futures price now being sixty cents a gallon) and the other industrial chemicals including naptha, jet fuel, asphalt base, kerosene (jet fuel, basically), waxes, lubricating oil base stocks and more. There are over 6,000 products made from oil and natural gas and only a few of them are considered "life-critical." All the rest of the businesses that use those products have been, in many states, ordered closed.
The problem is that the refinery cannot choose to only make diesel; the other products come out of the system at a more-or-less fixed percentage ratio. It can be shifted somewhat, but not very much. Those products have go somewhere, and if there is no demand for them because you've shut the economy down where do you put them? The answer for a very short period of time is in a tank, of course, but tanks fill up! Now what?
The refinery must shut down, that's what.
Oh, you said you wanted diesel so the truck can move food? Well now, we seem to be all out of that but I got a big tank of bunker fuel over here and one of gasoline over there, nobody wants either, and I can't turn the refinery back on until I can sell that and get it out of here so there's somewhere to put what will come out of that pipe over here when I turn this thing back on. What, you mean that big truck won't run on gasoline? Well that's sad, because it's all I have! Oh, incidentally, since everyone else has all that too guess what -- that diesel is going to be pretty expensive when I have room to turn the refinery back on since all the rest of this stuff is worth zero!