This series, like Huckleberry Finn, To Kill a Mockingbird, and others, are important artifacts and teaching tools about how society once viewed things. Not knowing and understanding our history dooms us to repeat it. Why not teach the Chronicles critically?
But really, most kids today don't even know these books exist because they are too blatantly Christian for secular parents; there are better, more contemporary fantasy options; and kids don't really read long-form, serial, analog content (chapter books) anymore. The kids that do/did read them are typically deeply disappointed to learn that the simple, fantastical adventure that enchanted them was really a multi-layered, pro-Christian propaganda piece for kids. We never saw the biases, or even the Christianity, when we were kids reading it, and we certainly didn't take all of Lewis' baggage with us into adulthood just from reading a couple of pages in his fantasy book series. Lewis just doesn't have that much pull or power.
Again, why not teach the Chronicles critically? This book series, taught critically, could have to power to unwind biases.