For proponents of putting religion in schools, why isn't Church and the home enough? Why must religion be taught in schools?
First, it is important to distinguish between the different ways that religion can be included in education. Now, I have this feeling that you are referring not to the folk who wish simply to teach about religion(s) in school, but to the folk who would like school to serve as a promoter of a specific religion (in the U.S., it is often some conservative, extremist, fundamentalist form of Christianity).
In terms of the latter group, I believe their primary aim is not to increase religion in the schools, but to decrease education. By pushing their religion into the classroom, they subtract time from other academic disciplines that they feel are immoral, such as science, sex education, history, math, etc. By replacing these blasphemous school subjects with something clearly non-blasphemous, they feel they can push out the invasion of modern immoral education in schools and thus save their children's souls... from the boogieman, no doubt.
Most would likely rather do away with public schooling entirely. Indeed, many do just that, not by destroying it, necessarily1, but by removing their children from the public schools to either indoctrinate them in the comfort of their home or send them to CCoI avoidance schools, where the worries of Satan's army of teachers no longer exists.
Jon __________ 1 Of course, the goal of public education being to educate the public, when groups of folk refuse to partake in the activity, they, in effect, destroy it by working against its goals.
"Can we say the chair on the cat, for example? Or the basket in the person? No, we can't..." - Harriet J. Ottenheimer