It's totally member-driven. I have no part in it.

Apparently it's private because there's a FB-User<->Guild-User lookup table in it. And FB forces you to either make everything private or everything public.

A page would be a good idea. I'd create one if I was guaranteed it wouldn't spam my personal timeline.

It would actually be something I'd keep up with, but I seriously abhor Facebook's obsession with depseudonymizing everyone.