You're right. The problem was never really fake news it was more that a significant chunk of the population has abandoned consensus reality. This is not a US problem either. I travel a lot and everywhere -- Europe, Japan, Australia, India, and the US -- you see the same exact pattern played over and over. Right-wing partisans lose all trust in the established media[1] after decades of right-wing politicians insisting that journalists can't be trusted. Right-wing partisans deliberately constructing their own parallel knowledge community and this enables right-wing politicians to speak, completely unchallenged, about events that never happened and facts that aren't facts[2]. The end-game, where right-wing voters, having isolated themselves completely, begin to insist on more and more outlandish conspiracies[3] until we're talking about secret pedophilia rings and the Pope conspiring with Hollywood Jews and millions of fake voters voting in the most closely watched election in the history of the planet.
The interesting thing about this process is how deliberate and effective it is -- and I think, if you spend time on these right-wing forums, like yourself, you start to realize that nobody has been "duped," these people aren't fools, they are eager and willing participants in engineering a state of mass delusion. This was very apparent to Deleuze who grasped this very clearly:
Reich is at his profoundest as a thinker when he refuses to accept ignorance or illusion on the part of the masses as an explanation of fascism, and demands an explanation that will take their desire into account, an explanation formulated in terms of desire: no, the masses were not innocent dupes; at a certain point, under a certain set of conditions, they wanted fascism, and it is this perversion of the desire of the masses that needs to be accounted for. (Deleuze and Guattari 1977: 29)
Like the war on drugs it is nonsensical to focus on the supply when the demand is so great. A population addicted to fake news, a population that wants to be propagandized, a population that will gather online in forums and message boards and
self-propagandize, is going to find and consume fake news and generate conspiracy theories no matter what.
And I think a liberal society has to let this happen. It's not like China, the State is not going to deploy its own highly-trained, well-paid "media operatives" to find and destroy this alternative media ecosystem while lavishly funding the official media ecosystem. The whole point of liberal society is that desire is allowed to run its course.
[1] https://techcrunch.com/2017/03/19/as-hyper-conservative-medi...
[2] http://www.cjr.org/analysis/breitbart-media-trump-harvard-st...
[3] https://www.buzzfeed.com/craigsilverman/how-macedonia-became...