Indeed, the test scores of homeschooled students are as high for those whose parents never went to college themselves as for those who did. Rationally, of course, professional educators should welcome the help they are getting from homeschooling parents, and they should be happy that the kids they don't have to worry about are doing so well. Taking more than a million children out of the system means more money can be spent per head on those who remain, and it means that teachers can give those for whom they continue to be responsible more attention. But that's not the way it works. The current educational system is into quantity, not quality.
More students mean more money and more union jobs.
More kids translate into demands for more funds for classrooms and equipment. That's why Berkeley is going after the kids not attending their schools. It has nothing whatever to do with child welfare or education - it has to do with jobs, money and power. Private schools, school choice and now homeschooled kids. They're all a threat to a bloated, but incompetent, educational system that is perfectly willing to ignore success in favor of its own bureaucratic interests.