It’s a comment on USMC’s present role, not on ability of personnel.
GI - “a member or former member of the U.S. armed forces, esp.” (but not necessarily) “an enlisted soldier.” Random House Webster’s Unabridged Dictionary, 2nd Edition, 2001
The G.I. form indicates “government issued” - op cit
There are problems. As I said upthread as a 4 year Navy guy in no way shape or form was I ever a soldier. The core of my being says that is Army. A Marine is a marine, maybe just maybe in the loosest terms possible he is a soldier but only because he too wears cammy and has a gun.
In a bar all bets are off.