There is a lot of bad that can come from them. People just think up reasons that may be good and they really don"t make much sense. School uniforms are pointless because they take away from people's individuality, some people can"t afford them, and they would make school boring.
Everybody needs his or her own personality. People must have individuality to not be the same as everyone else. Everyone needs to be he or herself and not be everyone else. It would be like having 300 people following a new fashion trend that looks goofy. Everyone needs individuality.
I know some people who don"t get to go to stores like Abercrombie & Fitch. Not everyone can afford to buy expensive, preppy clothing. Some individuals can"t spend $300-$400 on clothing every year. Also, think if someone hit a growth-spurt and had to buy a whole new set of uniforms. Not everyone is made of money.
Everyone enjoys change every once in a while, regardless if it is clothing style, furniture, getting a new car etc. If everyone came to school looking the same as their classmates every day, it would be incredibly boring. You have to let people wear what they think expresses them best. People need an occasional change. .
So, like I said nobody needs school uniforms. They are pointless and expensive and they would result in no change and no excitement in clothing. If you required them, more bad would come than good. Not to mention the defiance you would have to put up with. Nobody needs school uniforms.