Brevity is the soul of wit

I just watched The Forgotten, a rather average movie. Before the movie started playing, a bright blue screen declared that the movie was "Rated PG-13 for intense thematic material, some violence and brief language." So what exactly is the MPAA trying to protect children from? Do they think that if children are exposed to brief language, they are more likely to become reticent, incommunicative teenagers? "How was school today?" "Fine." "Do you have any plans for the weekend?" "Yes." "Really? What are you going to do?" "My girlfriend." Or perhaps they're afraid that brief language will make children prone to be being concise and to the point? And this is some kind of coorporate conspiracy to keep people from learning how to say what they mean instead of blathering on for minutes without letting slip a single meaningful idea? I can't guess what they're up to, but I doubt it's something wholesome.