Oh, I just had one more thought: Some homeschooled kids I met really were lacking social skills and it was often blamed by outsiders on the fact that they were homeschooled.
In some cases, the causality was the opposite: The kids had bad social skills (for whatever reason -- Asperger's, Autism, late emotional development) and that's why their parents had chosen to homeschool -- because in school, those kids spent all their time in the principal's office and didn't really learn much, except to label themselves as "bad kids"...