So...I assume killing other human beings is legally wrong and considered morally wrong in whichever society you live in. What makes it magically ok to kill other human beings that live outside of human-created borders that believe in different things than you.
I'd like to start off by saying that I do not believe that all killing is automatically morally wrong - obviously I'd have picked the wrong trade if I did. I believe that violence should generally be a last resort, and that usually (to quote Terry Pratchett) once you've drawn a weapon you have very few choices and they're all bad ones. However, it's legally wrong because Her Majesty says it is, and as a member of the Armed Forces you become, in effect, an extension of Her Majesty's wishes - as a country we 'draw a weapon' as soon as we send troops into war, and every member of the Armed Forces has sworn an oath to obey the lawful orders of his superiors. That means both that if you're told to open fire, the law and your honour (amongst other factors that I won't bother with) say you have to, and that (unless the order is blatantly unlawful) you are protected because the legality of it has been cleared 'above your pay grade' and so the fault is with somebody higher up (this works for orders such as 'invade Iraq' - no matter what you think of the legality, the lawyers for the Government say it's OK, so you have to do it - but not for 'shoot that unarmed child', because that's blatantly against the more limited set of laws that you actually have to obey)
What have you done to reconcile differences with these "enemies" by means other than violence?
In nearly all situations, the Government will have tried peaceful means first. It's not good PR to see soldiers coming home dead or wounded, and it's also bloody expensive to pay for us all to ship out somewhere. Personally? In some situations, you've shouted 'Halt! Halt! Halt or I shoot!', but in a proper shooting war nothing at all. They're not personal enemies; they just happen to be on the wrong side - which means that you will do your best to kill them while they're doing the same to you. Once the fighting stops and they surrender, you treat them with civility in accordance with the laws of war, because
it's not personal.
Isn't it odd to refer to one's self and one's relevance to society as an "instrument"? What's the difference between a local person that annoys the living guts out of you, has threatened to hurt you/your family, and expresses "radical views" as compared to your own, and between someone, say 2,000 miles, across a sea, an ocean, or a mountain range that has done the same?
HM the Queen has told you explicitly not to touch your irritating neighbour, but she has equally told you to shoot on sight the foreign terrorist if you see him armed. We have a police force for domestic incidents
What specifically prevents you from firing your rifle on the local a-hole while you feel morallly ok with firing your rifle on the a-hole across the sea, or mountain range?
Again, I wouldn't be OK with just shooting any foreigner I didn't like. As I said, it's not a personal grudge; fighting wars is different to the FIPAC that you see on a Friday night in Soltau. Orders are orders, as it were. The enemy has signed up to the same contract as you - you take the free (well, in practical terms) food, the free living space and the pay and in exchange you agree to fight and, if neccessary, kill and die when told to do so. I wouldn't consider it morally wrong for an enemy to injure me (luckily, the only battle-scar I ever sustained was
after I left the military!), because when I took the Queen's Shilling I quite literally signed my life away.
Do you just do whatever your government tells you to do?
Your oath says that '
will observe and obey all orders of Her Majesty, Her Heirs and Successors, and of the generals and officers set over me' (no mention of politicans in that, note), which international law amended to 'all lawful orders thereof. To some extent your conscience comes into play; it is actually illegal to obey an order that you know to be unlawful, but as discussed above (no doubt Mobby can clarify the precise legalese of it) there are certain things for which the response is 'stop thinking, man!'
Do you just like collecting a paycheck deriving from simple taxpayer dollars and that's what motivates you?
No... I'm pretty sure I've discussed at length what led me personally to join up and what kept me in for so long, but if you're in it for the money you'll never last.