why is there a certian dress code at school?

why is there a certain dress code is the question. the reason is girls made it were we got dress codes because they wore "inapproiate" clothing when i dont see why it matters what they wear. When they made the dress codes it wasn much of a fight from the guys but the girls fought about it because they can wear certain clothing now because i think parents and some students wear complaining what they wore but bottom line i just dont get why there are certain dress codes.