This is in part because Sebastian Junger, who co-directed the film with Tim Hetherington, is that rarest of birds: the macho hunk journalist.
Before it became a wildly overused metaphor, The Perfect Storm was the title of a book that Junger wrote in 1997. Three years later, George Clooney starred in the movie version and Junger's career became golden.
He writes about tough men doing dangerous things; his companion book to Restrepo - which was the best documentary winner at this year's Sundance Film Festival - is titled simply War.
For parts of 2007 and 2008, he and Hetherington, a Vanity Fair photographer, were embedded with 2nd Platoon, Battle Company, 2nd Battalion, 503rd Infantry Regiment (Airborne), 173rd Brigade Combat Team.
All that boils down to 15 guys spending most of 15 months behind sandbags and plywood on a mountain ridge in the Korengal Valley in Kunar province of northeast Afghanistan.
The place was known as OP (Outpost) Restrepo in honour of PFC Juan S. Restrepo, a 20-year-old combat medic who was killed shortly after his outfit landed in the Korengal in the spring of 2007.
Restrepo is experiential, as we film buffs say. There is no narration, no context, no explanation of what's going on except that offered by the soldiers themselves. Thus, unlike most of the movies about America's experiences in Iraq and Afghanistan, it is utterly apolitical. You see what you want to see.
If you want to see a handful of young Americans doing a cruddy and dangerous job on a mountaintop, that's what you see. They're scared, you bet, but they do their jobs. They laugh, they joke, they wrestle, they shoot people and people shoot back, almost every day.
OP Restrepo was hacked out of a mountaintop in a single night because Captain Dan Kearney, Battle Company's commander, needed to extend his firepower further up the ridge. Capt Kearney calls it heroic, and it was, because it took some of the heat off the headquarters base 800 metres away at Outpost Korengal.
But what is Company B doing there? You sort of have to guess at that. Capt Kearney tells the Afghan villagers that he's trying to protect the valley so a road can be built through it that will bring progress and make them rich. This is what he has been told, and a good officer does what he's told.
Things are more elemental for his troops: Hold the insurgents at bay long enough to bring some progress to the Korengal. Try not to get killed and, for godsakes, try not to kill any civilians.
This is Afghanistan as experienced by soldiers: Do what you're ordered to do, don't let down your buddies, don't ask questions.
There is heroism in that. Small-unit discipline is what makes soldiers fight. They may sign up out of patriotism or because they need a job or for any number of other reasons. But they do their jobs not because they believe in some grand ideal, but because they don't want to let their buddies down.
Thus Restrepo is a soldier's-eye view of the Afghanistan war, but it could be any war. It is war stripped of politics, free of nuance, full of tedium and terror, without context. But you can't watch this film without asking yourself the question that soldiers aren't free to ask: Is all of this worth it?
A couple of scenes hint at the complexities. An old Afghan man struggles with a foil envelope of Capri Sun, unable to figure out how to access the delicious fruity American concoction within.
And as the credits roll, we see the head being hacked off a cow; a cow that had stumbled into the concertina wire around Restrepo and been declared hors de combat and sliced into steaks; a cow that a villager wanted $US500 in reparations for; a cow the army wouldn't pay for.
We're spending tens of millions of dollars a day on this war, and we can't pay the man for a cow? Here, have a Capri Sun instead. No wonder they don't co-operate with us.
As the credits roll, the film-makers tell us that the United States abandoned the Korengal Valley in early 2010. They give us no other context; you have to look that up for yourself.
You'll find tragic misconceptions and lack of cultural literacy. Ignorance of hyper-local political realities and religious beliefs. That US troops may have been in the Korengal, as Greg Jaffe reported in the Washington Post, as "bullet magnets" to draw insurgents' attention from other places.
Soldiers don't know things like that. It's not their job. Their leaders are supposed to do that. Their leaders are failing them.
