Because the only thing today that they have in common with the Navy is the govt. leadership (i.e. Secretary of the Navy).
Besides the Marines fight in Land Locked countries all the time. The last time the US Marines where just pure "Naval Infantry" was probably 1865. The USMC has Artillery, Armoured Corps, Attack Aircraft, Fighter Aircraft, Infantry, Engineers, Spec Ops, etc...
Not sure why he erased his post. There was nothing wrong with it.
US Marines are/were part of the NATO defense of Norway and have/had equipment prepositioned there: Marine Corps Prepositioning Program-Norway (MCPP-N).