This is a great thread-lots of sides to this story and some valid arguments-
Was it excessive? Yes. Could this have been avoided if she listened? Yes.
Do kids nowadays see authority the way we did? No.
Here is a question for you-
How would you feel (honestly) if this was your daughter?
Was it excessive? Perhaps. Was it worth firing for? I don't think so, not based on that alone.
Often times when reviewing videos of force used by cops, I think "I wouldn't have done it that way" which is true. But it doesn't render the officers actions wrong automatically. Was it a violation of policy? Was it excessive? Was it an abuse are things we focus on and often times officers won't agree, just like citizens may not agree. Obviously there are the ones that are so blatant it obvious, like shooting the guy in the back when he is 20 ft away and running away. Or the elderly gentleman Patel who was violently slammed to the ground, but I don't think this one fits that mold
If it were my daughter, I would be shocked she disobeyed a teacher, principal and a cop. I wouldn't pat the cop on the back should I pass him in the hall, may not be thrilled about it but I wouldn't hold it against him.