This is a good move. US personnel living in Japan use scarce resources just like all Japanese residents. By moving US citizens out and deploying the ships Japan has that many fewer people to supply with food, gas and electricity. While parked on a pier, a US ship uses shore power (electricity) and water. Underway, they have their own power systems on line and make their own fresh water. IMO it's better for all to deploy the ships and send dependents home. FWIW, my opinion
Better is the Enemy of Good Enough.
Okay, what’s your point??