Of all the disturbing things this show has done, there hasn’t been a detailed, in-your-face instance of any innocent bystanders paying a price. Sure, there was Jane’s dad, who crashed a plane and killed a bunch of people, but there wasn’t much tangible about that; we never saw people burning alive on a plane or crashing to the ground (that would’ve been pretty bleak, even for this show). The most we’ve seen is the crack addicts or dealers who occasionally kill someone or one another and they’re not "innocent" in the same way. Gale may have been the most innocent person on the show, but he was still a meth cook.
People are people and every death is a tragedy, yes, but it doesn’t hit home. We, the viewers, are mostly law-abiding citizens. We don’t do drugs (OK, most of us don’t), we don’t skirt the law, and we don’t kill anyone. Therefore, we don’t identify with the drug dealers or the addicts or any person who, to this point, faced direct, tangible repercussions -- i.e.: death (and on camera) -- for decisions they didn’t make.
Most of the people in the series do terrible things and don’t see the repercussions of their actions—especially Walt, our "hero". The one character who’s the most closely related to us, Jesse, has a conscience, but he’s still a cook and he’s killed. He does harm to other people. In "Dead Freight," we have a boy killed in cold blood, whose only crime was he wanted to motorbike through the wilderness. Everything about him was supposed to be the definition of innocence and childhood. He even wears a helmet because he feels safety is important (or his loving parents do).
And it was a horrible twist. It was a tragedy. It was disturbing. It was necessary. It was amazing TV.