Government schools ARE evil in themselves, because imprisoning children for most of their waking hours for most of their childhood is intrinsically evil. And “education” is not a legitimate function of government. And it is immoral for citizens to use the taxing power to force other people to pay for educating their children.
Which means that government schools are evil in themselves on at least three counts.
It's legitimate (though not necessary) when it plays a subsidiary roll assisting parents who are the primary educators of their children.