Anonymous posts a crystal clear comment about the dilemma facing some (many?) Orthodox parents:
Sending a kid to a school with opposing hashkafas is a recipe for disaster -- I speak from personal, and close-second-hand experience. The poor kid, unless he is VERY strong personally, will be pulled in 2 directions, both of which are fraught with existential problems: If he disobeys his rabbeim, he is disobeying God. If he disobeys you he is disobeying God, and in effect spitting on the people you told him to respect and to whom you have entrusted him. And this is just the tip of the iceberg.