In reading these comments, and reflecting on past experiences, I think that what really worries people is proselytizing. I doubt anyone really begrudges allowing a church group or religious organization to use the school's physical facilities. The problem is that this all too often incorporates exploiting the overall set-up to foist a religious point of view on everyone.

When teachers and other school officials participate, even to the small degree of handing out permission slips in class, there is an implied endorsement of and a subtle (sometimes not so subtle) pressure to join with the group. In many cases, the peer pressure among the kids to join is intense. Most people don't want some church that they haven't selected trying to teach religious views to their kids. They particularly don't want to have to guard against that in a public school, which the great majority of folks are legally and economically compelled to send their kids to.

If a group would just have their meeting and leave others alone, I bet there would be no opposition. When they try to recruit kids to their beliefs and essentially shove those beliefs down their throats--and believe me, that happens a lot--people are going to squawk.

People feel they have a right to be free from religious proselytizing in government sponsored institutions. Too many religious groups seem all to willing to trample on that right and then moan about their rights being violated when they are denied access to such places as a public school. When the government facilitates their activities, say by allowing them to use schools to hold their meetings, it becomes a partner in establishing (partially) a religion.

"Your right to swing your arm around ends at my nose." These folks don't seem to care about anyone else's nose. If they did, I don't think there be any uproar.