Facebook, fake ads and the death of democracy

Mark Zuckerberg's position regarding Facebook is that it is not a ‘media’ but a ‘platform’ which facilitates the conversations of others, so making it more akin to a phone company than a media brand.  Therefore, unlike traditional ‘media’, Facebook has no editorial responsibility - or liability - for the content or the advertising it carries. 
Accept this at face value and it all sounds quite reasonable doesn't it? After all, a phone company isn&rsqu