Warfare is nothing new; this book is proof of that! Thousands of years ago an ancient Chinese general wrote this work and its principles are still true today. However, its not the book that bothers me;its who is reading it. Do we really need to have children learning such principles at such an age? We need less violence today, not more. Consider the words of Solomon...
Proverbs 22:6 (WEB)
6) Train up a child in the way he should go, and when he is old he will not depart from it.
Be careful what you have your children learn, you may not like the results in 25 years! Having said that, I know we need soldiers and police officers for protection. Both are honorable professions, but couldn't we wait a little before the indoctrination begins? Remember a little organization called the "Hitler youth"? Don't remember, pick up a good book on the subject; you might want to do a google search on Hitler first....