"school uniforms result in more/less emphasis on learning"
Some suggest that school uniforms automatically resulted in more discipline, but even if this was the case, discipline resulting from having no choice is rather empty anyway. Also,
it is questionable whether discipline in itself was desirable from an educational perspective.
Some also suggest that school uniforms resulted in less peer pressure and thus placed more emphasis on learning.
However, while school uniforms may reduce some kind of peer pressure, they increase other types of peer pressure between students.
Some suggest that school uniforms reduced discrimination, bullying, violence and crime, but there is little or no evidence in research to support that. Anyway, these are different arguments that are discussed in more detail elsewhere at this site.
School uniforms may impose some sense of equality upon students, but whether this was desirable is a matter of politics. It's inappropriate for a public school to impose one specific political view, while silencing the opposite view.
Mandatory school uniforms at public schools are prone to violate inalienable rights, including freedom of expression and the prior right for families to decide how their children are to be educated.
"School uniforms place emphasis on learning." [source]
"Not when the majority of the kids and parents are upset and angry that they have had a uniform policy forced on them by the minority. Then the kids go to school with the overwhelming thought of THE UNIFORM POLICY - not education. I am sure it is different in a private school, because the students and their parents enroll in said schools with the understanding that a uniform is part of the deal - they also have the CHOICE to go to another school where a uniform is not required. However, when you are attending a PUBLIC school and you have an unwanted uniform policy forced on you and you have no other alternatives (schooling-wise), well, let's just say it's a different outlook." [source]
"There is one deeper argument. It goes like this: students wearing uniforms will be accustomed to taking a servile attitude which will help them find work later in life. Of course, the very opposite could be argued with more reason. Does success in future demand a servile attitude? Or is it more helpful to be creative, have an spontaneous and open personality, an inquisitive mind, be a self-starter who talks things over, who has an independent mind searching for new ideas to make things work?" [source]