IMHO there really should be a penalty for spreading false news. It shouldn't just apply to mainstream media but also to "alternative news" sites and blogs that's becoming more prolific by the day. It's an open secret that politician's social media team hire these people to color public opinion. Their site creators makes blogs spreading fake news on a wide scale of topic, from ruining opponents reputations to claiming certain good deeds by the politician.
Their trolls, as expected, do stuff like post litanies on comments, gang up on people that criticize the politician, as well as harass people. In my country several journalists page has been shut down by FB because of coordinated reporting by trolls.
If mainstream media is to be held accountable to the news they publish, so should these "alternative news" sites.
So you support censorship? One of the core value of the american republic (and military empire)? How do you know if a news is fake? For example when clinton said, no no no.
I think that the path of freedom of speech is way more interesting for a society. It opens debates and a tolerance for others belief, a feeling of verbal counterstrikes, leads to great fun, and make the individuals more resiliant toward propaganda.