I can see your dilemma, and I think you did not slap them because you did not have the power. More than slapping them I guess "deleting" them from the whole equation would have been the neat thing to do, had we the power to do so :)
It is frustrating to see these scenes unfold. I wonder if some societies have finally outgrown this kind of behavior. Is there hope for humanity or will we always have to deal with the we-are-imperfect crap?
Why keeping great expectations about what humanity can achieve if we'll always be marred by our imperfections?