The story around "classical" Christian education is that it's about learning to think critically & analytically as well as teaching Christian doctrine.
I mean, they can't say "we needed our own religious schools, so we could keep schools segregated."
So that's the story: "all truth is God's truth: we can rigorously think through things, & we'll arrive at Christian conclusions, because it's God's world." Which makes sense on the surface, but obviously is not how that works.