Parents who homeschool connect with other parents who homeschool and have their kids hang out at the park or library or something. Kids can also play with their neighbors. You can still make sure the kid is developing social skills while they're being homeschooled, it's not that hard. You just have to try.

As another person mentioned, it was hard to do the social bit when they were all forced to stay at home. You can't prepare for something like this when it's suddenly dropped on you.