School choice is controversial because it is associated with right wing attempts to undermine public schools and, among other things, teacher's unions. In fact, the school choice movement as we know it goes back to desegregation in the south: https://www.washingtonpost.com/outlook/2021/09/27/school-cho....

That is just one article about it, but someone close to me was involved in the original litigation on the subject. It was not uncommon in the south for districts to close public schools and almost literally give public land and equipment from those schools to private schools which could more easily remain segregated.

There are other dimensions to school choice as well. In particular, some parents would prefer to "insulate" their children from information about sexuality or uncomfortable truths about american history.

And, I admit, public schools often are struggling to teach, so its not entirely black and white. But school choice is politically fraught.

But many people see it as the standard republican strategy: first, starve public services of funding, then claim that they are bad, and then get rid of them.