A ways back someone posted that homeschooled kids stand on the sidelines within sports team. Can't remember who the poster was, but I thought I'd offer a reason homeschool kids might be on the side other than the thought that they are socially retarded.
My son has been homeschooled all of his life. He's not the most extroverted guy, but I imagine that would be true no matter where he went to school. He joined a football league a couple of years ago, and I encouraged him to go hang out with the guys. (he did chat with a couple of them). On one occasion I asked him after practice why he didn't join the others. His response, "Do you know what they're talking about?" The answer, "Drugs, and sex." I am so happy that he recognized that he was better than this conversation.
Additionally, he has commented that other kids, "have no discipline". He's been in the company of plenty of other kids, (football, swim team, church functions)
Private and parochial schools today are not helping kids live up to their fullest potential. They have lots of societal/cultural stuff working against them, but the fact still remains.
Not everyone can homeschool, it is a full time job. But the idea that kids are better off either social or academically at school has no basis in fact. The evidence that public schools are a mess is overwhelming (some exceptions aside). The evidence is building that homeschooling is better academically (some exceptions aside) as the movement grows.
Homeschooling is far more "mainstream" than it once was, and the results? Well, the proof is in the pudding, some exceptions aside.