No, but you do get the virus being in close proximity to others. Whether on the beaches, in the parking lots, or in nearby stores and restaurants, you sure as hell do.
The problem is not the beaches and he doesn’t need to close the beaches per se. Its that people on the beaches need to practice social distancing. There are lots of beaches on Florida where you could walk for miles and not see another human.
Large gatherings and failure to practice social distancing are the problem.