The massive deployment of our navy remains a mystery. Your idea is on the short list of my theories, sort of like a reverse blockade in the hopes of snagging the enemy before they can enter our ports. My other thought is that the home ports are just too susceptible to nuclear attack, which could do a lot of damage to our fleet if exploded within a mile or two of the target. Norfolk/Hampton Roads, is a major commercial shipping, rail, and trucking location, which provides a lot of oppurtunity to put a nuke very close to our Navy. The same can be said about the Groton/New London area. Explode a nuke in either area, and a lot of ships go down, unless they're out to sea.
Launching a missle from a couple hundred miles out from a ship would be easy to do.Even 50 miles out, they have access to those rockets via Syria, NK and Iran. We have a very long coast line.