However when public education is not guided by improving meaningful outcomes, but by ideologues, it needs to be checked. Vouchers sounds like a good way to insert some market dynamics and to allow parents to walk away from schools that are on the path to fail to prepare their kids for the future.
As opposed to parental ideologues? By letting parents choose, we'll be letting them go to different schools championing different value system and the customers will be parents, not the children they ostensibly are charged with educating.
By grouping parents with like-minded parents, we'll amplify groups and clusters, leading to not only further stratification but also further decoupling society and greater inequality.