They need to be treated (and told!) like the are a “common carrier” they have no say over user content. The old phone companies had no way of controlling what you said, FaceBook should not be allowed to control what you post. If FB is worried about losing business because users don’t like the posts then that’s just the way it is. FB should say (BE REQUIRED TO SAY IF NECESSARY!) don’t look at them, block them, ignore them otherwise we can’t help you!
There is nothing preventing someone from competing with Facebook. Just like there was nothing preventing Facebook from competing with Myspace.