Even though it's much more expensive to lose a lawsuit over an issue than it is to resolve it through customer service, most people choose not to sue. Facebook can fulfill all of their current legal requirements by simply not showing up to any court hearings, losing by default, and paying whatever someone won. If that is cheaper than providing real customer service, they will do it. And real lawyers cost $100s/hour so if the amount FB has to pay is less than that they're losing money by showing up!
This applies to all companies, but the average Facebook user doesn't even pay for an account and are of even less value than a typical customer support line user (notably, the article says a benefit of "Facebook verified" which costs $15/month is actual support).