AFG is not "international armed conflict". The Muj operating there are not "privileged belligerants". They have no lawful "purpose/rationale" to kill. There is no "just war" and they are not "lawful combatants". Therefore, some muj shithead killing our guys is not privieged or immunized for warlike actions. The fact that we don't summarily prosecute these guys and then hang them from the gates of our outposts is yet another subject (that I will sidestep before my head exploedes in anger).
Doesn't seem to stop us from prosecuting our OWN guys though.....