One of the universal truths buried inside the documentary "Bully" is that at some point in their lives most people have both bullied and been bullied. Whether it takes the form of schoolyard taunts, workplace rivalries, various forms of discrimination or something else, you've probably experienced aggressive behavior from both sides. Bullying often incites more bullying, which is why it can be difficult to tell how much is too much and why the majority of bullying involving young people is written off by parents, teachers and administrators as "kids being kids."

"Bully" takes an emotion driven approach to exploring the topic of excessive bullying and although it doesn't dive deep enough into its subject, it's still an affecting piece of work well worth seeing by both adults and kids. Which is why the primary pre-release controversy surrounding the movie — the MPAA's decision to give it a R rating and the film's distributor The Weinstein Company subsequently deciding to release it without any rating at all — is so frustrating.

The MPAA has strict rules about how many times the "F" word can be used on screen, and for them "Bully" crosses that line. Rules are rules they say, context be damned. But here's the funny/ridiculous/maddening thing: the multiple uses of the "F" word in "Bully" occur in one particularly vivid scene of the film's lead subject — 12-year-old Sioux City, Iowa middle schooler Alex — waiting at the bus stop with a few other boys. As the bullies, who are Alex's peers in age, taunt and curse at him, going so far as threatening to kill him, Alex simply stands there acting like everything is normal. In his eyes, the boys are just "messing with him" (as he frequently explains to his concerned parents).

Let's make this clear. The very reason the MPAA assigned "Bully" a R rating — which means children under 17 need to be accompanied by a parent or guardian to watch the movie in a theater (at least a theater that properly enforces the ratings, but that's another issue) — is because kids who are clearly under 17 say the "F" word too many times. In a documentary. There is no explicit sexuality (or sexuality of any kind really), no graphic violence, no gratuitous language, no complex adult themes or situations that parents may understandably deem unacceptable for mature pre-teens or teens. And for that "Bully" receives the exact same rating as "Saw 3D," "The Girl with the Dragon Tattoo" and "The Hangover Part II." If that's not a sign of a broken — or at least nonsensical and unreliable — system in need of an overhaul, I'm not sure what more it would take.

All the hubbub over ratings has become something of a distraction from the film itself. If anyone comes for the controversy, they should be prepared to stay for the touchy feely activism. Director Lee Hirsch ("Amandla! A Revolution in Four Part Harmony") certainly knows how to push buttons for maximum emotional impact. From a mother's harrowing recollection of the day her bullied 17-year-old son committed suicide to the remarkable everyday struggles of Alex, just a normal kid trying to fit in with peers who refuse to accept him, Hirsch captures the insidious nature of bullying and the way some kids simply grow numb to it (with untold damage to their psyche and sometimes body) while others go so far as suicide to find release.

What this focus on the victims makes "Bully" less successful at illuminating is why bullying happens in the first place and how it can prevented or at least alleviated. So much time is spent detailing the obvious fact that bullying exists that it overwhelms the more interesting moments captured by the filmmakers: an assistant principal telling a bullied kid that he should just try to make friends with his bully, an investigation into the verbal and physical abuse Alex suffers on his school bus that reveals various levels of cooperation and compassion from his classmates, Alex's younger sister explaining to her befuddled brother that she gets made fun of because kids think he's so weird.

Almost all of the film's strongest revelations occur in Alex's story, the one true vérité throughline to the film. A few kids from other areas — including 16-year-old lesbian Kelby, ostracized by her community for coming out, and 14-year-old Ja'Meya, incarcerated and charged with multiple felony counts for threatening bullies with a gun — are chronicled in more controlled "drop in" interviews, but in casting a wider net the film starts to feel scattershot. A simple focus on Alex could have resulted in a more cogent and complex film.

Nevertheless, "Bully" succeeds at the most basic goal of any advocacy doc: raising consciousness. And even though it ignores uncovering the cause of the problem, or really grappling with the question of whether or not bullying is worse today (are we nastier as a culture? has the Internet made things better by uniting people who struggled to connect in the past, or worse by offering new outlets and opportunities for bullying?), "Bully" still confronts its audience with a simple plea for personal responsibility. Maybe you've been bullied and maybe you bullied, but the indispensable message of Hirsch's film is it'll get better when we all do better.

"Bully" opens in limited release Friday.