In war, any mercy you show threatens the lives of your side. Sure, it's nice to have some cooperation with the enemy, but at the end of the day they are trying to kill you. I'm not questioning war crimes, but rules are meant to be broken, and at strategic times.
Look back to when Egland and France were fighting over the the New World. Here's the Brits, all lined up perfectly in line formation. And here's the Natives and the French hiding in trees like Ninjas shooting the fuck out of them.
America's army wears camo, as opposed to the majority of history's armies, which almost never used worn equipment for the sake of stealth. I personally would rather wear something more flashy or badass, but you should always take any opportunity to increase your chances of victory.
I wouldn't kill a medic or the wounded. Not all soldiers medics help get back into combat. Statistically speaking, ammo is better off being directed at other soldiers, or the soldiers helping the wounded. I know it seems cruel to treat people with lives and families so harshly, but their objective is to kill people with lives and families.
All this talk about war is killing my buzz. Let's bust of the hippieness.