Some people would claim to be shocked by this simply because it has been filmed. However, it's a fight between schoolgirls and is nothing new. But when I went to school there was no such thing as YouTube but fights were fairly commonplace, albeit the majority involved boys.
Bullying is also nothing new. It is to be condemned, no doubt about it, but it has also been going on since who knows when.
We don't know all the facts of this particular matter, hence it would be too easy to be judgemental on the basis of a piece of amateur film footage. It's a fight, no more. If one party wishes to lodge a complaint, the relevant authorities will investigate and deal with it. Let's not blow it out of all proportion.