Too lazy to read the article, but I'm betting this is just for Bootcamp. What they're probably looking at is what I think the Army does, which is to address Drill Sgts as "Drill Sgt".

In the Corps, it's "Aye aye Sir". They'd probably replace it with "Aye Aye Drill Instructor". There's no way they're going to expect recruits to know ranks during the first couple of days.