In Hosea 2:4, God says, “I will not have mercy upon her children; for they be the children of whoredoms.” The children in question were Israelite youth who had been born into and were growing up in an apostate church. They were church kids who had grown up in a syncretistic church which had tacked the verbiage of the religion of Jehovah onto the pagan social and religious values of the surrounding heathen nations. This made them illegitimate children of the covenant.
If this doesn't describe the last couple of generations of American evangelical kids, I don't know what does. Many, who have grown up in church, have grown up with the verbiage of Christianity tacked onto the same values as the surrounding secular culture.
Youth ministry is one of the biggest demonstrations of this bastardization of the worship of God. The unspoken assumption of typical "youth group" ministry is that God exists to make you happy in the enjoyment of whatever it is you happen to be “passionate” about. What do the children of unbelievers value? What are they passionate about? Sports, movies, bands and singers, video games. What do church youth groups busy themselves with? Sports, movies, bands and singers, video games. In the final analysis, the focus is on the dreams, desires, and ambitions of the “worshipers.” It is a utilitarian religion that uses God as a stepping-stone to what we really want.
This is, in many ways, not very different from the focus of much of the grown-up oriented ministries. The ultimate reality is you and your dreams. God exists to help realize these things. That's the heart of Canaanite paganism (all paganism, in fact). You scratch the back of the gods and they'll scratch yours. Paganism is indirect self-worship. It is the “worship” of a deity whose sole purpose is to give you what you want. Dressing this religion up with words like “Jesus,” “sacrifice,” “commitment,” “fellowship,” “disciple,” etc., doesn’t make it any less pagan. It’s still spiritual whoredom.
If your kneejerk reaction is to object that sports and music aren’t inherently evil, then you’ve missed the point (and most likely, the boat). No one is suggesting that youth groups become hermitages where the youth hand copy ancient manuscripts and wear hair shirts. But when the youth pastor’s skills include the ability to chug Mountain Dew, recite lines from the latest hit HBO show, kill at chubby bunny, and don’t include being “mighty in the Scriptures,” we’re producing the next generation of children of whoredoms. We shouldn’t be terribly surprised when the leave the faith. They never had it in the first place, nor was it ever presented to them.