She’s not allowed to dance offsite at a private party but if you go to the school’s YouTube channel there are a couple cringy music videos of all the staff dancing (including the principal) on school property during working hours. www.youtube.com/watch?v=3qjnPeUOMjo
And why was he even watching these videos in the first place. They would have just been fun videos the friends made to share with each other outside of school. This was just about him being turned on by watching an under age girl dancing and then punishing the girl for his feelings.