If memory serves, FB was set up so that freepers could gather in the event that this site went down.
I don’t use Facebook, but I’ve seen the FB Free Republic site a couple of times over the years when FR was down for a while.
But we’ve seen in recent months that Facebook censors stuff, too. What would stop any other, new site from being censored or interfered with?
If you want something completely independent of control, you’re going to have to come up with a brand new technology.