foremost. Some do all the teaching but many do not. Many are using varied resources for teaching and instruction. They aren't preparing all the food, but they ARE controlling what is on the menu.
Second, look at what average or below-average kids are "taught" in public school. And then look at what they SHOULD be taught. And then look at what they ACTUALLY do learn. They are ALL very different. O-D's claims about the public schools implicitly, and falsely, assume they are all the same, or nearly so. It's hogwash.