There it is again

In a political piece on Romney,

Romney himself never served, and his unfamiliarity with military issues is evident in “No Apology.” He proposes adding “at least 100,000 soldiers to the army and the marines” (Marines are not soldiers).....

In what sense does the word 'soldiers' not apply to people who walk around town in uniforms collectively shooting people? Americans are peculiar on this issue; they really seem to have a cultural twist that makes it impossible for them to envisage a world without 'marines', as if, say, Australians had another colour that nobody else could see, or the Welsh had up, down, sideways and cwmf.