Hate to be That Guy, but it TECHNICALLY says that using them against CIVILIANS is a war crime. Unfortunately, they already justified killing and harming everyone as "enemy combatants with some collateral damage"

It's basically the "it's okay that we killed that kid, they use kids with bomb vests as weapons so they were actually a combatant!" defense I regularly heard about the War In Iraq while growing up

but "we treat everybody as combatants" doesn't have much support in international law