The drill instructor must have total and complete control. Mindless obedience is what he's after.
It couldn't be a simpler answer. Marriage doesn't really mean anything to me. I feel like in many ways marriage is more for the families of the couple than for the people involved, so I don't gravitate to it.
That's one of the great privileges, being an actor, is that someone pays you and sends you off to learn about something that otherwise you'd never know about.