The picture I was trying to paint, albeit not very well, was that there was no group that we could trust to decide which things people should be allowed to say, and which things they shouldn't be. (I didn't get the point across very well, so we ran in to a race condition after I decided to retract it. Sorry.)

If we think that Facebook should decide what's permissible, then that's US culture being the global nanny. If we let the local government decide what's permissible, then you better watch out because every single genocide in history has involved demonizing the victims as the real danger (so, their speech would be pointed at as "harmful" and banned, the perpetrators would be painted as organizing a just revolution). The worst genocides were conducted with state support, and wouldn't be stopped if local national governments were moderating Facebook. Forming a special panel to decide which groups deserve to get their message out seems like a very dangerous and poorly motivated concentration of power. I can't think of any other ways to decide which speech is dangerous and ban it, therefore I conclude we're stuck with not doing it.