So, you may have a point in what you say. Let's get specific. But I don't think they have any business teaching values that are specific to particular religions. The issue of sexual behavior can and should be addressed in sex education classes. I don't see why any of this should be done within the context of religion.
Sexual behavior is always a tough thing to regulate.
This is a responsibility that really lies first and foremost with parents. Only they can make sure their kids are home in the evenings doing their homework, get to bed at a decent hour, etc. By the way, the ACLU seems way off base here. One can consider it the prudent exercise of good judgment. Heck, these days it's a public health issue.