How was this film anti-gun?

I didn't get the anti-gun vibe from this film. Maybe I missed it but it just seemed to revolve around the school shooting that happened, and the effect it had on the families of those involved, and the dangerous life that inner city children have to face. I don't recall any specific scene where one of the characters claims that non of this would have happened or been possible if guns were banned. Did I miss something that would give people this feeling?