If it isn't, it should be.
The United States is a signatory to the Child Soldier protocol. The United States therefore acknowledges that child soldiers can and are made to believe and do just about anything their adult mentors wish. The United States therefore accepts that child combatants are to be treated as victims and, as such, agrees to furnish child soldiers with protection and rehabilitation.
So why, with Omar Khadr, did the United States turn its back on everything it acknowledged and undertook to do in signing the Child Soldier protocol?
Omar Khadr was not treated as a victim but as a war criminal. Khadr was not protected and rehabilitated as the United States was obliged to do. To the contrary, Khadr was housed within a community of radical Islamists where, by the prosecution's own witness, he was even further steeped in their beliefs. In effect, the United States did just about everything conceivable to ensure that Khadr is today more radical and more dangerous than ever.
And now they blame Khadr for supposedly becoming everything that was entirely foreseeable from their own indifference and neglect.
Denying a prisoner food or water is a war crime. Why should denying a child soldier protection and rehabilitation be any less a war crime?