Why is it ok for people to shop at Walmart and not at their local small business that sells the same goods and is better equipped to enforce social distancing, with customers explicitly opting in to visit the smaller store?
If a small business can protect workers and customers, and a comparable large business is already open, the small business can consider opening and preparing to litigate all the way to the Supreme Court. With video cameras ready.
There may be a few hundred bored lawyers who remember the US constitution and would take their case pro bono. The federal government recently said it is willing to join lawsuits against states, on constitutional grounds.
Obviously, the business in question should be carefully chosen to maximize health, legal and business outcomes. But with many businesses shutdown, there's a large pool of candidates to be triaged.