Ben Levi, you are illustrating the pitfall of a lack of education (although to be frank, I think you’re deliberately lying about not having graduated high school). You don’t know from your personal experience whether public schools do a good or a bad job of educating people generally. As a famous economist supposedly said, “The plural of anecdote is not data.” Additionally, as someone who (supposedly) dropped out of high school, you almost certainly have a confirmation bias toward the notion that PS education is deficient.
Moreover, even if it were true that all public schools do a terrible job of educating every single American child, that would not absolve the chadarim from their duty to provide a good education to the children they serve. Nobody made the argument that we have to learn science as well as the non-Jews do. We’re just making the argument that we have to learn science.