Why are American Schools so Free?

I have had many opportunities to visit schools in America. When I go to a school, I always think that American schools are so much more free than Japanese. When I was a junior or senior high school student, I had to follow many school rules. For example, we had to wear uniforms, and we didn't dye our hair. It was too strict. However, in American schools, students are free. They wear casual clothes, their hair colors are many, and they can bring snacks and their cell phones, so I'm jealous of American school students.

American schools are free in terms of not only break time but also courses (lessons or classes). In Japanese schools (except college and university) curriculum is regular, so we can't choose classes. But in America, students can choose their classes. It is good but I think it is difficult for young people. Now, I'm a university student, so I have to choose my classes. It is good but when I plan my curriculum, I am always confused. If I had gone to an American school, while I could enjoy life, I probably would have had a difficult time to study.

In other words, I think that American students live their own life and school is free, so they have to choose many things. It makes students grown up. However, in Japan, students are not free, and they don't have to choose. It is easy for them, but I think American school is better. I hope Japanese schools will become more free like in America.