Schools allow students a variety of choices. While the parents in this article may believe that they are allowing their students a variety of choices in their development that otherwise wouldn't be available. I would argue to the contrary. Allowing students to choose from a small set of experiences may actually shelter them from interests that they didn't know they have, In our school we have a variety of career focused electives that allows students to fall into something they didn't know they were initially interested in. Some of these classes include, a publication class where students create daily announcements, and learn technical skills that are used by real broadcasters. An engineering class that exposes students to the field of engineering through hands on creative work. Students typically love this class and a typical day in this class looks something like this..

To me this looks like all kids are engaged in their learning. None of them look to be suffering too much.
Schools expose students to dynamic personalities. This is a bit of an age old argument, that homeschooling limits kids socially. While I don't believe that this is an absolute truth. Typically the homeschooled kids that I have come across are lacking something socially. People are very different and have a wide variety of traits and skills. School exposes kids to this. Teachers are all very different and bring a variety of styles and expectations. I think that it is important for students to learn how to interact with this variety. In the real world we constantly learn what we can get away with, or how we can relate to our superiors. Home-schooling only exposes you to one type of these types of personalities.
I also know that at my school students are exposed to a large amount of diversity. The other day I was coaching football, and noticed that on my team we have Caucasian, Hispanic and African American players on our team. I also noticed that the cliques of players on our team had nothing to do with the race of our players, but rather who they are as people. I think this is something that home-schooling shelters kids from.
I am not saying that public schools are perfect, and I recognize that not all schools have the programs and initiatives that my school does. I think schools can focus a lot more on allowing students to be a part in picking their own path. I would also love to see the pressure placed on kids in standardized testing disappear because I think its counter productive. However, I think that the idea of home-schooling, or "un-schooling" as the author refers to it as, might only work for a very limited amount of students.