You don't understand abuse, particularly of a child, but this thread obviously isn't going to help you. It takes a long time for someone, particularly a child, to gain the strength and self-esteem to stand up to such abuse, physical and mental, and say 'enough'.
Releasing this vid took a helluva lot of courage because the potential ramifications were obvious as well as the potential criticism for releasing it.
That said, I don't know if you feel this person deserves to be made accountable or not, regardless of how this went down. He certainly doesn't feel he should.
Releasing the video took no courage. It was probably posted in a rage tantrum when she figured out the gravy train was over. If she released it without blackmailing him about it, I would probably agree with you. However, this is nothing but a spoiled little shit having a knee jerk reaction to not getting what she thought she was entitled to. I know the behavior, I have a teenage stepdaughter and any time she doesn't get her way she blames everything on somebody else and will do whatever it takes to get attention or what she wants. Once again, I don't agree with physical abuse, but you are blind if you think that girl posted the video with any other intention than getting some attention and getting back at her father for not getting her way.