In his helpful book "Why Christian Kids Need a Christian Education", Douglas Wilson explains why this is a bad move. While the desire to protect our children from the world is a good one, we should proceed with caution. He writes,
"The mistake arises because there are a bunch of sinners that parents [really] should keep away from their kids - kidnappers for starters, and cocaine dealers and pornographers, and seducers and Cartesian dualists. One of the accusations leveled against private Christian education is that conservative parents are sheltering their kids. What next? Parents sheltering children! We feed them too.
"But here is where the mistake comes in. There is a question of degree here. We are not supposed to keep our children away from the presence of all sin whatever. And that's a good thing, too, because it is impossible. There is a type of sin, common to the human conditions, that your children will encounter (on a daily basis) on the playground of the finest Christian school imaginable. If you refuse to send your kids to that school (because of all the sin there), then they will encounter even more of it at church, in their relationships with their siblings, in their bedroom all alone, and in the midst of all the dirty little thoughts between their ears.
"The task of Christian parents is not to avoid that kind of sin, but rather to teach their children how to battle it. You cannot learn to battle something if you are constantly endeavoring to stay away from it. Running away is not the best strategy here.
"Suppose your child is in the classroom of a fine Christian school. You know the teachers... and they really love the Lord. But you know for a fact that two-thirds of the kids in your son's class are all hot about the latest shanky movie. Just last night, after the youth group get-together, they all went to see Shanky Movie III, one that has set records for both kinds of box office gross. What will the temptation be?
"Your temptation will be to think that however well intentioned the folks running the school might be, the 'tone' of the school is not nearly 'high enough,' and that all these families clearly have poor standards. You regret having to do this, but you are considering pulling your son, wrapping him up in cotton batting for the two final semesters of Mom School. You think the problem is low entertainment standards, when the actual problem is that no Christian parents - including you - are teaching their kids what moral leadership looks like.
"About a third of the kids who went to that movie didn't really want to, and wouldn't have gone if someone in the class - I am thinking of your son in particular - had done more than simply studied his shoelaces when the subject came up. You are tempted to think that the others have low entertainment standards, when the real lesson is that your son is not a moral leader. The response ought not to be to do something that will make him even less of one."