You seem like a smart person with an interest in this case. My advice to you is to look for original information, rather than relying on other people. For example, look up the "child soldier law" yourself. See what it says. The US Military Commissions website has thousands of documents on this case. You don't have to rely on some second hand source. You can see what the US actually charged K with and why. You can read court decisions. You still might feel the same way about the case, but you'll have better arguments, your own.