By all accounts New York seems to be just about the worst affected place in the world.
The rest of the U.S. less so.
But if it's in the U.S. and rampant in such a diverse city, with so many people potentially travelling to/from so many different states, towns, cities, areas across the country, it makes sense for all/large areas of the country to put in place restrictions.
It's less about the current overall state is nationally, and more looking at New York and one or two others and saying, "let's stop that happening in Madison, Des Moines, Austin, El Paso, Baton Rouge, Auburn, Bismarck, Dallas, Boston, etc...".