Trying to raise one's children Catholic with an intentional and graded introduction into a healthy, spiritually mature relationship and attitude toward the flawed, but graced world and culture in which we live is subject to the temptation to make family life a “total institution.” Ashley and O'Rourke define it in Health Care Ethics: A Theological Analysis, (4th edition) as a "closed social system where people so live within a rigid set of determined ideas and behaviors that they are cut off from contact with a reality beyond and different from their limited perception. This often leads to a distorted, paranoid way of perceiving and interpreting the world.” p. 362. I see this temptation is the some overly critical and restrictive reaction to books like Harry Potter.
I know some families that live pretty much like that and all seems well, in fact, almost idyllic from the outside. And maybe it is in those cases. It is certainly a good idea to be very clear about the standards one expects from one's children and to hold them accountable to those standards. It is also very important to initiate your children into a Christian world view and to emphasize those books, movies and other sources that are consistent to a Christian world view and to associate your children with people who live that world view. The Schoenstatt movement has a concept called the ver sacrum, or sacred springtime. They believe (and I agree) that in the world in which evil influences are endemic it is important to withdraw to a certain extent in order to form one's mind, will and imagination with healthy, Godly influences--even through college! And, further, there is some stuff out there that all Christians should avoid for their entire life--such as pornography.
But does that mean that your kids should never hear a Beatles song because of the Beatle's immoral way of life or because of their rejection of Christianity or because some of their songs are immoral? This is a tough call because if you listen to the beautiful "Here, There and Everywhere" with your preteen kids, they will want to hear it all, including "I Am the Walrus." Also, it gets tiring for your children to always be evaluating every single entertainment choice you make against the standard of moral propriety. Heck, it gets tiring for me to do so.
I think there are two points one can make about this. The first is that our Lord does not want us to be afraid. If fear is the driving emotion in your family culture--thinking that the least little exposure to problematic material will doom your children to hell, you are probably not trusting God to fulfill His promises concerning family life. Second, growing up and learning to relate to our actual world is risky. We've got to let our children become subjects of their lives, making choices on their own about what material is spiritually harmful to them. I think our culture and our kids want this to be done too quickly and too early, but it still remains an important principle of child rearing.
Oh, and I'm pretty sure we shouldn't let our kids' flack determine when and how we loosen restrictions. They really aren't yet wise enough to know what the real dangers are.