(Unless you've homeschooled, I don't think you have any idea how much social interaction homeschool kids can get; we don't just sit at home all day.)
Edit: I see comments below on homeschooling and from homeschoolers. Our kids get a ton of social interaction outside the home: homeschool co-ops/events/park days with other homeschoolers, language lessons, sports (karate, soccer, equestrian), music lessons, girlscouts/boyscouts, university outreach programs, town provided activities (acting, choir, pottery, etc), temple, playing with all the neighborhood kids, and that's just off the top of my head.
My kids are 9 and 11 right now and are way more comfortable socially, and better at it, than I (public school) ever was.
Ultimately I think a lot of it has to do with the kids and the parents. We chose to homeschool our kids because we think we can do a better job with their education, but it certainly hasn't hindered them socially.