It seems that a local school district has a dress code that prohibits girls from wearing skirts that reveal higher that where the arm falls naturally to the side, so mid thigh. Boys, on the other hand are permitted to wear shorts, but after a certain point in the year. The school officials have not been enforcing the girls half of the dress code, but the boys were still not able to wear shorts. The boys, as a protest, wore kilts to school. Hey, I say whatever gets them into a kilt is a good thing. But they were, in fact, sent home for inappropriate dress.
Let me try and understand the situation.

The girls are getting away with wearing skirts even shorter than the allowable length, and the boys want to wear shorts, but were not allowed, so they wore kilts instead.
Is that about it?

Is your concern that the girls skirts are too short, or that the boys can't wear shorts, or that the boys are not allowed to wear kilts?

Our school has a uniform, I believe in uniforms, they prevent, if nothing else, a whole swag of rediculous fashions at school and problems associated with that.

I think a school has the right to enforce a dress code provided it is reasonable and acceptable to the majority of board members and parents.
Our school is a private school, small and easy to manage so it may be different.

I think our school would allow a kilt if it fitted in with school colours, but these lads you speak of just seem to be protesting rather than expressing a real desire to be kilted.

Let me know if I have it wrong.