One thing I think you missed out on, Nicholas Grossman, is that Facebook (and social media broadly) is not simply a venue for propaganda; it is also a means of surveillance. The two are interconnected.
Many have already written on the deluge of fake news, but what has not been adequately discussed is how that fake news landed so perfectly in the Newsfeeds of the Trump base. What is perhaps too big for people to understand is that moreso than any other factor, Facebook’s bulk data collection served that purpose. That data is not simply what people volunteer to Facebook; that data comes from anything that matches the email and phone number you provide Facebook and which leads back to marketing lists (from data brokers like Axciom, Lexis, etc.)
The Trump campaign (and plenty of petty grifters in its wake) likely targeted any number of marketing lists you wouldn’t necessarily think of as “political” but which were easy pickin’s for the shrillest lines. It is incredibly easy to agitate scared white folks by
a) coming up with the shrillest headline (e.g., “BOMBSHELL: Hillary promises Obama to enslave white men after election”), and
b) serving it up to a receptive audience by simply targeting owners of pickup trucks in Michigan and Ohio.
(Another wrinkle: it’s trivially easy to make sure that as few people as possible from the opposition ever see the ad. Facebook allows the ad to not appear to certain demographics, including women or people with specific “ethnic” affinities.)
Knowing this kind of stuff was going on before the election is one of the reasons I chucked Facebook. Because, quite simply, I never gave any consent to them going through my pharmacy purchase history or the like, but I am almost certain they have that data and allowed it to be used for marketing.