If a voucher system is not in place, if a family wants their children to go to a religious school then they have to pay for it out of pocket while still paying taxes to their neighborhood school. If vouchers are allowed, then parents can take some of the money that would normally go to neighborhood schools and use it to help their children go to religious school. By making it easier financially, vouchers inadvertently support religious schools.
Education vouchers wrongly support religious schools. If parents want to send their kids to a religious school, then they should have to pay for it out of pocket while still paying for public schools. It is the parents choice to send them to a private school, but they still need to pay their taxes.