Hey, reasonable minds can differ. I don't think he handled this well. I think what he did was childish and attention-seeking, rather than a sincere effort to help his daughter back on the path toward becoming a responsible adult. While I think that his frustration will resonate with many viewers, I don't find it an example of good parenting.
Lots of teenagers bitch, including the whole "what am i, your slave?" attitude. They are in that awkward stage of no longer being children but not yet having the perspective and experience to see the bigger picture. IF it was normal teenage bitching (and I'm not saying it was), then this is an extreme over-reaction.
As far as her behavior, I don't think it anywhere merited this level of response. Was she stupid to think that filtering her Facebook page would prevent him from seeing her letter? Yes, especially since it sounds like she had already been busted that way once. But really, all she was doing was venting her frustration to a select audience of her Facebook friends. There's nothing to suggest, for example, that she is doing drugs, committing crimes, skipping school, destroying property, etc. If she had been at the mall and said the same thing to her friends orally, would he have been so ticked off? What if she passed a note in class to her friends saying the same thing? She didn't post it on his Facebook page, or on Youtube, or at his place of work.
So let's assume it is not normal, and Hannah is out of control way beyond the norm. How about taking some personal responsibility? Somewhere along the way in the past 15 years, dad failed to teach his daughter some important values (with which I generally agree). If his past lessons were anything like this one, I have an inkling of why. Where is his humility? Where is his acknowledgment that maybe HE screwed up as a parent and that it is not all about his wild child daughter?
I'm probably more critical than the average person of parents who divorce when they have kids. I know there are astronomical divorce rates, and I know there are plenty of relationships where it is the right thing to do. I also know that it very often has a bad effect on the kids, and can scar them for life. I think in many situations, parents divorce and then when their kids act up the parents fail to take personal responsibility that something they did -- whether it was the decision to divorce, the acts leading to the divorce, a remarriage, or something else -- screwed up their kid. If I were a parent who decided that divorce was the best thing despite the fact that I had a school-age kid, I think I would be forgiving and supportive when I saw my kid having behavioral problems, knowing that I may have largely contributed to them. I certainly wouldn't be posting lessons for other parents on Youtube as though I were a paragon.
I have no idea for this father and daughter what the circumstances were for the divorce, and maybe it had no impact, but I find the father's reference to the mother and stepmother noteworthy. I can't really think of any scenario where what he did is the best way to handle the situation as a parent.