This is not a section on how to fulfill your child's need for other people. You can do this with neighbors, community sports, scouting, co-ops, local park days, playdates, church, even within the family. A homeschooled child is not an isolated child. People that hide away all day and keep to themselves are the exception, not the rule and that behavior even disturbs other homeschoolers. We are, by nature, a curious and social group of folks.
Children don't need 20 other children exactly the same age around for hours a day to be socialized-we all know that is not a model for the real world, it is just a convenience for the school system to assume that every 6 year old is exactly the same as every other 6 year old and therefore wants to learn and do exactly the same things. You don't even get that kind of luck out of identical twins, much less a room filled with 20+ totally individual people that are treated as a bulk.
School crushes the very nature of a child out of the child. Conformity is enforced from the very first day. Curiosity is not nurtured because it is in the way. You do what you are told, you don't seek the answers to your own questions and worst of all, you are assigned topics to be interested in. Schools were created to provide basic education, true-but they were designed to provide it in a way that made the student learn from the start to do as they are told, not to question instructions, not to interrupt, not to be an individual. In other words, they cranked out good little factory workers. The basic school has not changed in the last 100 years. Would you send your child to a doctor that was trained 100 years ago? Why would you trust their education to a system that is just as archaic and potentially as dangerous?