Expanding on what [@Bork Lazer] said, I could summarize my view simply by saying: [b]you're allowed to make readers uncomfortable.[/b] You have the opportunity, you have the right; in fact, if you're trying to say something important about a real, difficult topic, then, to be honest, you have the duty.

[i]Come and See[/i] isn't the best anti-war film ever made because it's polite, it's fair/balanced, and it holds wittle baby's hand through a gentle acclimation into the topic. It's the best anti-war film ever made because it does none of that. It forces you to watch women and children be locked in a church before molotov cocktails and grenades are thrown through the windows. The camera lingers on the church until well after the screams have stopped. You see a man still squirming and writhing when his blackened body has been pulled from the char. You watch a woman be dragged behind a Jeep, then stumble out ten minutes later with blood and semen dripping down her legs. You watch rape, infanticide, desertion, treason, and the expected, comparatively tame act of putting bullets and shrapnel in people. Experiencing human cruelty at its peak is crucial to the film's message.

 ... or you look away from the screen, which in itself proves its point. Because if you're the type to look away from a movie when it gets uncomfortable then you're also the type to look away when your politicians order the deaths of thousands in combat, and war-criminals have torched an Iraqi village, and hundreds have been reduced to widows, orphans, and refugees. You might even be the type to glorify war when it's clean, convenient, thousands of miles away; when it chases noble abstracts like "honor" and "justice"; less so when you have to face the reality of what devastation war wreaks upon flesh-and-blood [i]people[/i].

Could such a story be told through euphemism, innuendo, trigger warnings, and censorship? Maybe, but it would be a diluted, de-fanged version of the story we ultimately got.

The brutality and the horror need to serve a purpose, though. Violence for the sake of shock value, edge, or worse, popcorn entertainment, is a waste at best, and a travesty at worst, a hollow, meaningless effigy which infantilizes the audience and dehumanizes the people who actually suffer such things all around the world.

TL;DR Dark imagery and themes are good when making the audience uncomfortable serves a greater artistic purpose; bad when they're superfluous or superficial.