Well, the common carrier approach would not necessarily mean that every user can publish what they want.

Common carrier treatment arises when you control a unique piece of infrastructure, or, more loosely defined, a dominant one. As a result you need to provide non-discriminating access for competitors.

In my interpretation, this requirement would also be satisfied by Facebook allowing publishers and companies to create pages. A minimal threshold of importance that's equal for all page owners might be valid.

And the paper touches on this, mentioning that there's a valid role in moderating comments:

> There might thus be reason to leave platforms free to moderate comments (rather than just authorizing users to do that for their own pages), even if one wants to stop platforms from deleting authors’ pages or authors’ posts from their pages