Casey took that bully out, LIKE A BOSS.
As others have said, just watching the video itself is enough to tell that Casey wasn't thinking 'I NEED TO PILEDRIVE THIS KID HEAD FIRST INTO THE GROUND' and that the reality was more like, 'Fuck you dude, I'm gonna hurt you so you stop'.
Honestly, when I first saw the vid, I just expected a flat out fist fight to break out or at BEST, the little kid to get slammed into the wall. That throw to the ground clearly was an inhibition brought about by the frustration OF said bullying.
Both of them are alive and 'that' is what matters. Casey gets a moment to realize that while what he did wasn't the best solution, it was likely his only solution at the moment. That kid is currently being publicly humiliated for being an asshole to Casey and if he doesn't come out of this LEARNING from it, then I say fuck him and let natural selection run its course on the bully.
It's not every day a kid gets to be somewhat of a hero. As long as Casey doesn't take this and turn it into a belief that HE could be the bully, that's all that matters. He's set a reputation for himself and it is plain and simple, 'Don't fuck with me'. And really, that's all 'any' kid could REALLY ask for in school.
Also, to the mother of the bully, give it up. Your kid deserves to feel stupid for this for the rest of his life. No one deserves to forget and lock away their mistakes. Know why? BECAUSE YOU LEARN NOT TO REPEAT THEM.
That video being around with be the best form of a reminder for your little fuckwit of a son to not act like an idiot again. And if you really think your son is all that great, I'm sure his facebook page would 'totally' agree with you.