There's no provision requiring that media companies publish or don't publish any views at all. FCC content regulations only apply to broadcast media, and trying to get similar content regulations on non-broadcast media would require passing a new law. Even then, those regulations have only been moral issues (nudity, sex, violence, naughty words), not viewpoints. Nothing stops Fox from having Alex Jones or Glenn Beck on to say whatever they want, and Fox doesn't become liable in the libel suit if a guest on an opinion show libels someone. That remains the problem of the individual unless that individual is speaking on behalf of the company.
There's also no special regulation requirig media companies to "share" or "use" anything in particular. If a news station decided not to broadcast 9/11 coverage, nothing happens to them. There are requirements for broadcast licensees to broadcast emergency messages, and we have libel laws still, but neither of those apply to social media.
Was there a specific example you had in mind or a specific regulation? What would Facebook or Twitter not be able to do, or be required to do? And what regulation would be used to reclassify then as a media company, since they don't have to have broadcast licenses?
