Perhaps this quote from the article of the same name explains it all: "... [by 5 years old,] public schools become a reliable source of child care...."
That's a rhetorical "really." Public school has been a reliable source of childcare since it was no longer necessary to educate factory workers (like, say, since the 1950s).
Homeschooling is attractive because the child is more than a number and their needs are met by people who care about their success. Homeschooling is attractive because the focus is on learning, not testing, and there are all kinds of options to get from point A to point B, not one way that only works for certain students.
The animosity directed towards homeschooling of late is a bit puzzling. Homeschoolers are called elitist or isolationist, unrealistic and tunnel-visioned. People assume homeschooling families are rich and religious. There are lots of misconceptions about homeschooling, what it means, how it is done and who does it. Before you criticize and denigrate, do a little research; you may be surprised. If the best public schooling has to offer is "reliable childcare," perhaps it's time to become more fascinated with what happens at public schools and less concerned with the work being done at home.