Facebook is the most miserable place online. I deleted my account because of the continuous energy sapping, followed by relentless attacks -- even while not online myself! Oddly enough, it stopped once my account was entirely closed. Simply "unfriending" the offenders wasn't enough. Not by a long shot.
It would be highly advisable for them to seek refuge here. You have certain things going for you that they don't. Of course they would be as open to DoS, DDoS or general hacking attacks as anyone, but they would be more subject to advanced persistent threats (shills, subterfuge, etc.) on a dedicated site, simply because they aren't as developed to see "who is who". As you say, you're working in the lion's den there. There are those with strong reasons to keep things on their terms. A dedicated nest would be an ideal incubator for wiles of all descriptions to be employed. Now is the time for the light, not for creating pockets of darkness.