There's none of the financial worries, pecking orders, or time constraints of workplace friendships, plus more of the freedom. You do it, supposedly, once a week, or more. There's no pressure to make small talk because you're there for another purpose as well, so if you get uncomfortable, you can just leave. As you get more involved, you start joining committees, planning events, coaching teams, going on retreats, leading the local Boy Scout troop, participating in Bible studies, etc and are able to bond with adults there. As long as you're set on your denomination, there's no reason to leave while you're still in the geographical area. Your kids can encourage interaction with other parents, and if they stop being friends, they'll probably still be forced together through sports/school/service events. And you're operating on the same general life philosophy as all of them--supposedly.
When my parents moved, their "friends list" literally became a subsection of the church directory.
Church literally fills every requirement in the article, since it's a very social event with a purpose besides being social for its own sake. I'm amazed the author didn't mention it. Well, not too amazed, since there's nothing more socially unsexier than church groups. I know most people here aren't too warm on religion but it sure knows how to built community.