Don't quite understand David. You still haven't explained why that means experience is more important in defending that attacking. How is reading the game and being more "battle hardened" any less important as an attacker than a defender?!
Much of what a striker does that makes him effective is based on his skills with the ball, or his pace. You don't need experience to have those things.
History has shown us that defenders take longer to develop into top class players because experience is so much more important.
That's why there are no defensive equivalents of the likes of Rooney, Owen, Walcott etc getting into the England team at a young age.