WARNING: DEFINITE AND SIGNIFICANT SPOILERS AHEAD.
Antoine Fuqua doesn't like government or politicians, and the bigger they get the less he likes them. Shooter, as if evidence were needed, is an anti-government polemic wrapped up in an action flick, with a hero (Mark Wahlberg) Bob Lee Swagger, a former sniper and a man possessed of simple ethics and deadly skills. The government is a present-day one, instantiated in a grossly-overweight 'US Senator' (Ned Beatty)—who likes to proclaim this every now and then like a creed and declaration of his license to act with impunity—plus his henchmen, led by Danny Glover, as Colonel Johnson, as an ice-cold opportunist and manipulator. Not many shades of gray here. You know who the bad guys are and who to cheer for.
Bob, after having been used and left to die by his government in a mission behind enemy lines and seeing his friend and spotter die beside him as a result, manages to escape and tries to live a life alone in the mountains somewhere. He's sought out and manipulated into becoming a patsy/fall-guy for the assassination of a foreign leader, though it looks like he was after the US President. Hunted by everyone and sundry, and with the assistance of his former partner's wife (Kate Mara) and an FBI agent (Michael Peña), whom Swagger declined to kill when he might have, and who as a result starts thinking the wrong (right) thoughts.
Though Swagger must realize in the end, as must the audience, that here indeed, as the bad guys explain several times, we don't live in a world anymore—if ever! not on the large scale anyway—where the sheriff can fix the problems of his town with a few judicious killings, he does his best to make sure that, at least insofar as he himself and one other person he might still care about is concerned, he'll make sure that things are set as much to right as they can be.
As usual—as in Tears of the Sun and King Arthur, for example—underneath the action flick there lurks a polemic that pays homage to the 'simple' soldier; the man without grand agendas, who just, for whatever reason, wants to do the job he volunteered for or was dragged into by contingency; while being deeply cynical about the motives of anybody much above the rank of the truly 'operational' soldier—that being the ones who end up in actual battle, rather than watching it from a distance—and definitely of those elevated to the status of 'leaders' of human societies; be these leaders in the nature of 'emperors', as in King Arthur, or of democratically elected politicians, as in Tears of the Sun or Shooter.
I happen to share Fuqua's cynicism of these people, and indeed of everybody in 'politics', and so sympathize with the sentiments of the movie. But I also understand that a lot of people will ultimately find it uncomfortable and therefore will probably turn off it. This might also apply to many who otherwise would agree with Fuqua when it comes to specific politicians they despise, however, because he does not proselytize and pretend that there's actually much hope to change the world either. It is what it is, and though individuals may win their personal battles, the result is at best a glitch in the system, barely glimpsed and forgotten by the next breath. As such, Shooter is a bleak vision. Very satisfying on one level, because we see the scales of cosmic justice tipped a bit closet to the point of equilibrium; but we also realize that they remain disconcertingly askew, with little hope for change.
The movie is rated 'R' (in New Zealand, where I saw it, 'R-16'); not, I suspect, just because of the violence and the heads exploding with well-placed sniper rounds; not because of the sex, of which there isn't any; but mainly because in the end Swagger does something that many, who would otherwise have sided with him, must surely find disturbing, despite all the bad things the evildoers have done, as he goes on a calculated final killing spree. It is lawless and ultimately denying that in some things there can be any hope for justice—or, in this case, the assurance of personal safety—and that sometimes there is only one solution to certain problems. The audience will have to take that home and ponder it—if they see past the action/conspiracy flick at all!—and decide how they feel about it.
Personally, I'm cool with the ending; as I agree that some things sometimes just need to be done. As such I found the end 'satisfying', and I would have been disappointed had it gone any other way; say, as in Three Days of the Condor, which is even grimmer, more claustrophobic and hope-denying, reflecting the mood of the 70s, while Shooter has a much more proactive air about it, despite its hero being pushed into action by events, rather than causing them himself. Fuqua shows a disinclination toward 'meek' protagonists, which is cool with me.