I agree to give kids different religious options but I dont agree about " different subjects"
Do you mean that in Australia some schools are allowed to teach the kids that evolutionism is a false theory while creationism is the true one ?

If I understood correctly, this is , in my opinion, an abuse of the concept of democracy

Here in Europe, religious people can run schools but they are not allowed to choose the " subjects "
Obviusly you can not prevent the teachers to have some influence on the student, this is democracy but they must follow a common programm

This is what I meant, in my previous thhread saying :

Education is not a right, it is a duty

Nobody should be permitted to teach false theories