I'm over 21, with no kids. The dad crossed a line. I don't really care about the gun, I care about the publicity of the whole thing. He didn't have to go put the video on YouTube.
It seems like this wasn't an isolated incident in their relationship, and I understand that, over time, bitterness and resentment can build up if conflict is not dealt with healthily, and that can lead to overreactions. From the outside looking in, it seems to me that this is what's going on. That's not an excuse for him to do this, though. She made her complaints public and humiliated her parents on Facebook, but if he's going to be an effective model of grace and forgiveness, he shouldn't respond by publicly humiliating her.
What's your take on it, SRK?