This is why veterans of war tell you it's terrible. Not just because they kill people - but because sometmies they have to, and it's not fair, and it's not "right" - but it's war - and the other gut is just someone else trying to kill you or wishing you dead.
War sucks and it should be avoided whenever possible. That's the only conclusion I draw.
As to the comments made - I would like to see the unedited footage before I made up my mind. I bet some people in a war zone do feel elation at killing. It's a war zone. These guys are soldiers under pressure/fire and people are trying to kill them. I think it could happen to many of us if we lived under those conditions.
Cheers,
Andy