I'm not sure you understand what a tax deduction is, which is understandable, most people don't. Lets say your local store overpuchases perishable food by $100,000 in November, because fewer people bought from from them due to no SNAP benefits going out. They do not come out ahead. They do not even come out made whole by the IRS. They get $21,000 off their federal taxes for the year, assuming they made a yearly profit of at least $100,000. They still have to pay the supplier for their purchase.
ETA: I think the thought some people are having is, x amount of food is made in the USA per month, so x amount will be available for consumption one way or the other. Stores will donate to food banks their excess. So its a net equal. It might just about work out that way for a month, since no one knows how long this will last. But if its lengthy, I see a couple of things happening. First the USA, while a net food exporter, does import food. That will be cut. More food may be exported to other markets if demand for food goes down in the USA. Perishable food may be transferred to non-perishable status (ie canned or frozen) and held in inventory. That's on top of the fact that its extra work and less efficient to move food to foodbanks than just let people buy it with a SNAP card.
