If we'd look at the world map and see where the US—specifically where Hawaii was—and the Philippines—specifically where Subic was—they'd have to be in our area of responsibility, circle around the tip of Luzon just to reach the Subic Area. However, it was just a must for the US Marines because they had an existing naval base to their name while the ones who got ahead of them didn't.
'That's just to our knowledge though, they could be ex-Marines or somewhat affiliated with them for all we know…'
In addition, the opposite of where we are on the map—not to disparage them or anything—was mostly rural areas, and that came with more native speakers than English speakers.