Dress codes do help with what is on the clothing. Our school system has blue or white polo or button down shirts and khaki pants.
I'm amazed at what I see kids wearing in the mornings as they exit mom or dads car. The girls pants are so low they have to shave to wear them and their shirts aren't long enough to reach the waistband. Honestly, it looks as if the parents are turning the girls out to work the streets, not go to school.
Only because of what the Confederate flag has come to mean, I'd just as soon not see it or Malcom X or ANY political images on campus. There's already enough to distract the kids. IMHO, of course.
"Our school system has blue or white polo or button down shirts and khaki pants."
Sounds like your school system has uniforms rather than a dress code; or maybe you're saying that a supplementary dress code is needed to dictate how the uniforms are worn. If so, I'm not against that. What I view as unworkable (as evidenced by these continuing controversies about "inappropriate" slogans or images on T-shirts, etc.)is a dress code without uniforms.