I'm an Afghanistan combat veteran and I enjoyed the movie. It captured very well the emotional cocktail of:
frustration // we're here for goals that aren't well-aligned with the average sergeant, that our friends are being hurt and killed, that shit is going on back home and duty is pulling us in different directions...
fear // the man with the jacked up face in the hospital bed freaking out because he tried to push his girl away because she "deserved better"... that was on many of ours minds but men don't really talk about this shit very well. but given the nature of the threat in AFG (bombs), losing one's legs (or penis) was a very real fear and no one wanted to return from war as a dependent.
anger // a lot of things are a big WTF out there, can just leave it at that.
That scene with the brother on the tarmac, haunted look on his place "fuck this place man". It isn't what I'd call PTSD, but that feeling of isolation upon returning home. Think about how you could be helping out more and if you "deserve" to be back home. Think about things you could have done differently, that might have seen a friend come back home that won't be. There is a reason a USMC infantry battalion waits a few weeks before releasing its men on post-deployment leave: gotta keep an eye on everyone initially. That scene with Chris Kyle at the end where he's at the bar because he "needed a moment" and his wife is like "wtf why aren't you coming home to your family". Just thinking about it again makes me start tearing up.
Anyway I'll stop rambling. I think a lot of people wanted some deep commentary about the nature of war and weren't interested (or prepared) to follow a more visceral/emotional experience. I wonder what combat veterans as a whole think about it -- small sample size but I know the terminal lance (former USMC infantry) author really enjoyed it as well. I could absolutely see a civilian with nothing to draw on leaving that theatre thinking its "just a dumb propaganda piece"... but this story isn't really about MastaSniper 9000s kill count or how great our country is. It is about how a man like that feels; in combat and back at home.