we dont know whether the classmates were disciplined or not. the point is that this was something that was previously not a problem until certain classmates started acting like retards. in that case, the proper solution is to discipline them. if they still act up? discipline them more severely.
this situation is merely punishing the victim and showing how toothless the school really is when it comes to disciplining troublesome students.
However the the school is abiding by its own rules where it is stated in the article itself that the school has a policy in that any hair-style that brings a distraction or causes a issue in the school itself is also prohibited.
While those kids are wrong for bullying this girl the fact of the matter is when you look at the issue objectively her hair is causing a distraction and presenting issues for the school itself.
Hence why the school officials made the suggestion to the parents (who made several complaints) that they need to also reign in her hair-style. Furthermore you also have to consider in this story what the parents of this girl are asking for and what they were no doubt aware of when they first enrolled their child into this private school and that is the rules regarding hair styles.
In other words they want the school to ignore its own standards on grooming for their child's hairstyle that other students attending this school must adhere too, they want the school to ignore the issue and distraction this hair style created (even if it is unwarranted bullying), i.e. they want their cake and they want to eat it at the same time.
Additionally as Mr. Pedantic mentioned above in his post, why would is it not a issue when private schools require young teenage boys to reign in their "natural" hair growth that appears on their faces when they reach a certain age but in this case its a huge issue here because it involves a young girl? In the end there are many angles in this story that one has to think about IMHO and it isn't as cut and dry as you might think. However the shining positive point in this story is that the parents in this case have a choice to vote with their dollars and send their child to a different private school and this private school has a right to uphold it interpretation of its own rules and standards so as to not undermine itself in the long term whether or not you, I or the parents of this girl agree with how they applying and interpreting those rules.