Currently kids grow up for 18 years in a everyone-for-himself, in-order-to-be-successfull-you-need-physical-strength-and-iron-will world, and just then they switch to the much better and fairer world where being sucessful is not dependant on being able to defend your own flesh.
That adult system of self-fulfillment while not having to mind fighting bad guys all the time is the basis of our scientific and economic progress of the past 200 years. The big question: why do we put our kids into a different, unnecessery, dangerous and toxic environment for their first 18 years?