I am right. Going to write my representatives in the Congress on this. Think it's time to get the ball rolling on petition drive for this.
Federal law would have no bearing on this as it is not a federal government interest in the dress code for a high school graduation. What you are proposing is illegal in the first place.
Go ahead and waste your time, Rail against local control of schools. Rail against centuries of tradition. Just be an flaming asshole if you want. The liberals will love you for advocating their idiocy.