Schools have the responsibility to promote democratic values. Uniform policies are at odds with that responsibility.
Schools in the West are not just educational institutions, they are a way to pass on democratic values to the next generation and ensure the future stability of our democracy. Schools, therefore, should be places that adhere to the fundamental principles of democracy, including freedom of thought, freedom of expression, a celebration of diversity, and a commitment to critical thought.
The principles of religious freedom, freedom of expression, critical thought, and the right to protest are the pillars of Western democracy. In shaping the leaders of tomorrow, schools have an obligation to uphold these principles and create an environment where children understand their rights and the freedoms afforded in a democratic society. School uniforms, which stifle critical thought, reduce diversity and smother individuality, are in direct contrast to many of these basic democratic principles. Their enforcement, often carried out in a top-down approach without an opportunity to challenge or defend the rights of the individual, is also undemocratic and does not resemble the legislative or legal processes of a democratic society. Schools that teach democratic values should be participatory, allowing students to participate in the decision of what clothes they wear to school. They should be deliberative and promote discussion over what is acceptable and unacceptable attire, and they should be non-repressive. Uniform policies go against all of these terms and therefore have no place in Western educational institutions. 
The primary function of education is not to promote democracy, it is to equip individuals with the skills to become skilled workers and contribute to the strength of the economy. In a globalised economy, with competition for jobs coming from other nation’s workforces, schools that focus on democratic education are doing their pupils a disservice. They must channel their efforts to focusing on preparing their students to be competitive workers than can excel in a hyper-globalised world. 
[P1] Schools should promote democratic values. [P2] Uniform policies are not in line with democratic values. [P3] Therefore, they should not be enforced in schools.
[Rejecting P1] A school's role is not to promote democracy. It is to prepare students for the rigours of the workforce.