Today, some want to throw out these provisions. Times have changed, but principles have not. In colonial New England, some Baptists lost their farms and were jailed for not paying taxes to support the church and school, even when their taxes could support their own church. They insisted that religion must be voluntary, not coerced. Support for vouchers means support for coerced religion.
Religious schools exist to incorporate the faith into the life of the entire school day.
Tax support for these schools, our schools, is inevitably support for religion. We are forcing others to pay for our faith. That's wrong in any age. Forced religion is tyranny. If the state can force religion through vouchers, it can force other forms of religion, like forcing people to worship or profess a certain faith.