I disagree. Fortunately, so did the Supreme Court in Zelman v. Simmons-Harris. But, it was a split decision, 5-4. And it's a tightrope deal.
The gist is that the program had a secular purpose (education for low-income kids) and thus religious schools can be used in the mix. The same amount of money was allocated for all schools, public and private.
The SCOTUS ruled that the state's involvement ends, once the money is given to the parents. So, the choice of private schools is solely on the parents, not the state. As long as that's the case, there's no constitutional violation.
It is the law of the land and for that reason it must be accepted. As far as I am aware, at least in michigan, on average the amount spend per child is a higher than what most individuals pay in taxes intended for education. In this scheme, the money in each student voucher isn't representative of the taxes paid toward education. I may be wrong, so, this is a statement/question.
Going on a tangent in 3,2,1...
In a weird way this empowers the poor, who often don't pay taxes at all, than it does working class or higher income families who can afford to live on areas with better schools. At the same time, lower income parents who often have difficulty arranging adequate transportation wouldn't be able to take advantage of vouchers. Even if it they were able to take advantage of the vouchers, it doesn't necessarily mean private schools have to accept them.