To be fair it teaches them that they need a boyfriend so they have VALUE. Protection is secondary. Remember girls: You aren't valuable unless a MAN loves you.Literature that teaches young girls that their lives aren't complete unless they have a boyfriend to protect them.
Also: As much as I loathe Dan Brown, the man knows how to write short catchy chapters that keep you moving and never give you much time to really think about how stupid his story is. That *might* sound like an insult, but it really isn't. He doesn't pretend to be a great author or a master of his craft, he just knows how to write compelling books and he uses structure to make the reader plow through them at breakneck speeds, kind of like a big action flick.