I was taught that a Marine was a Marine, a Soldier was in the Army, an Airman was in the Air Force, and a Sailor was in the Navy.
As a point of pride each one has in his/her respective service, it is usually best to attempt to not get them too worked up. As I went to school with a couple Marines, I know they are usually very particular about identifying their branch quite proudly and enthusiastically. Semper Fi!
:joker: