Controversial School Policy-Bradley Roberto

I believe a very controversial school policy is the rule saying that you cannot wear hats unless it is an official Olympian High School hat because every student has the right to express themselves. Who gave the school the right to control what students wear? Apparently wearing a San Diego Chargers hat, as such in the image, is inappropriate or "gang affiliated." I believe that this policy should be completely changed because supporting your favorite athletic team has nothing to do with gangs, drugs, or profanity. How I would change this policy is that students would be allowed any hat they want as long as the hat does not promote anything inappropriate such as nudity, alcohol, or violence.