I firmly disagree with this advice as well; it strikes me as the sort of advice one comes up with when sitting around one's room wondering why one doesn't have any friends. The worst part about it is that it will get you doing all these activities that take up your time but don't really solve the friend problem.

Making friends isn't trivial, but it isn't a complex thing - just ask people you sort of vaguely know to hang out sometimes. Asking people to spend time together is about 10,000,000% more effective than any other strategy.