Parents have a right to decide where to send their children to school.
We as tax payers foot the bill to fund our school system. Why does the law prohibit us from deciding what school we want that money to be used to educate our children?
If we as parents decide that a particular school would do a better job of educating our children what gives the school system the right to force us to take our children to any other school?
School choice also incentivises every school to improve the quality of education they provide because they know you can choose to go somewhere better if they do not improve.