Not only did he overreact, I'd wager he's got issues, too. Here's why:
If you're a parent, you ought to feel like you're in control (i.e., I don't mean draconian discipline, but that your words carry weight) of your household. Therefore, discipline, while uncomfortable, should be akin to mowing the lawn in that both are things that 'just need to get done'. In addition, you should be aware of your own strength- that of your body, mind, and words- they are all greater than your child's. So even if your kid tries to hurt you, you should not go nuts and pound them into the pavement with extreme prejudice- if there isn't anything abnormal (the kid is a genius, mini-Arnie, sociopath, pyschopath) defeating them should not be a problem. This brings me to my point about the laptop; the girl humiliated her father in front of perhaps 10-20 people, tops (only so many could have known him and read the conversations). The correct course of action would have been to take her Facebook away while you figure out what the problem was, and how to resolve it. However, by posting that video and humiliating her in front of everyone who knows her (potentially on the order of 1,000 kids) he shows just how insecure he is.
So you see, the real problem was not whether the punishment was reasonable or not, but that the father is insecure about his position in the family. That's a real problem- feeling like you have to pound your kids into the pavement if they step up to you doesn't solve anything. Someone who has true power knows it, and exercises restraint, rather than get anxious and overreact when a weaker individual challenges them. Yes, I sound like Steve Erwin meets Dr. Phil, but it's the truth.
-Penguin