Schools have their own different identity. To prove the point, every school which wants to show that its student is different from other s of different schools. So to display their identity they have a different uniform.
Schools those have a uniform policy treats everyone equal. This also discourage those students who are from wealthy background and have the symptoms of showing-off. So the schools following uniform policy keep every student equal.
On the other hand, it is difficult for some people to afford expensive uniforms. People from humble background face lot of problems to fulfill the requirements of a standard uniform items those require extra money.
Clothing often reflects who you are and who you socialize with. In most schools, there are groups of students who dress alike. All the jocks dress differently from the preps who have a different style from the punks. You may even avoid a particular person because of what they are wearing. Uniforms require students to get to know each other by finding out about who they really are.
People also dislike school uniform because it stops their freedom. They can not wear any clothes of their own choice as uniform bounds them to only