If someone cares so little about the country that they do not want to live there, then they can forget about voting.
IMHO
When I was in Costa Rica a few years back, the local chapter of the VFW was hosting a thanksgiving dinner.
Strip him of his U.S. citizenship and make him live in Mexico!
It is the right of any American citizen to live where he or she may desire to live, and still be an American citizen.
They can work overseas with US or foreign firms, or they can be stationed overseas with the US military.
You should really give some thought to your responses.