Homeschooling children will interact with people in the context of their parents in all places in society their parents visit, and there are a wealth of groups and activities for the kids to join and interact with. Even better, the parents often have more direct insight into their childrens' interactions with others and can advise and support as necessary.

The whole 'needs socialising' claim is based on flawed assumptions, lest we assume all kids at school benefit socially from the environments they are in at school, which seems... optimistic.

Also, where else in society do you need to be measured in competence against other random local individuals of the exact same age?