Even in this not-so-good system, in which some people get taxed for a service they won't use, there is the assumption that if you have children than you have the right to be supplied with state-provided education.

Is the state decides not to grant you the service, for whatever reason, then it should give you the money it would otherwise have spent in order to provide you with said service. Else you are subject to discriminatory treatment by the state, based on your personal decisions.

The parents don't approve giving their child a vaccine they consider experimental/risky/unnecessary, they do this in full use of their reason and with the children best interest at heart. The State decides no to provide educational service to the child, but the child still needs an educational service. The right course of action would be for the State to give the parents the amount money it would hav spent, so the parent can contract the services of a private educational institution that would give the child the education the child needs.