If you are sending your children to Punahou, St. Louis, or Maryknoll you are paying taxes to support the public schools that your children are not using. And further, by educating your children in private schools, you are reducing the burden on and costs of the public schools. This is why the Secretary of Education under Trump is a strong supporter of school vouchers (the other reason is private schools give parents more choice including choice of religous education they cannot get in public schools).