Yes, homeschool children should have friends. But not just random friends. Homeschoolers have the opportunity to for selective socialization.
Parents can guide their children to other Christian families with like minded morals and values.
Most home school families I know are are very active with other families. There are weekly field trips with support groups, twice a week church functions, scouts, choir, weekly skating parties, etc, etc. Do Better Socially Information gathered by the National Home Education Research Institute prove homeschool students have significantly higher self concepts than those in public schools. And the home educated have positive self-concepts. The home schooled are well adjusted socially and emotionally like their private school comparison group.