Good point. It would be good to see a tree (or graph, it's probably cyclic at some point) of exactly how it spreads.
The left and the right have those as well (although calling Hillary and Trump supporters "left" and "right" is inaccurate, but that's for another discussion).
The "right" had "the protests are started by Soros" and so they saw buses everywhere for a whole week or so. There was another such thing for a "get paid $3.5k to attend an anti-Trump protest" that ended up as a fake CL screen capture.
The left first started with "let's hack the electoral college". There was a lot of discussion about that - "what if we convince/force them to vote the other way. Maybe invoke some hidden article from the Constitution..." or some thing like that. That went on for a while. It died down.
Then "fake news" started, almost overnight. And it's been fake news since then.
Just yesterday here there was some discussion about an oil field in Texas, and it seems they overestimated the cost or used a different metric or some such thing. But people here were calling it "Fake News". I thought it was initially supposed to lizard people controlling the government?
Then this story as another example. A major fuck up, everyone got worked about stuff without verifying. The source doesn't seem to have done it on purpose and has since deleted it (but it was too late) of course. Everyone in the chain begin idiots and overreacting. But NYT, CNN, CBS, FOX, NBC have been doing this stuff for years! Especially regurgitating anything coming out of the State Department or other government institutions. They are billion dollar corporation, if anyone can verify stuff it should be them. Would they consider themselves "Fake News"...
The problem is they are realizing they are losing the ability to manufacture consent like they could before. That must be terrifying, so they have to respond or do something about it. "Fake News" is their response.
To be fair, is a useful PR technique - a label that can be quickly thrown on anything. This makes sense also in the context of how popular Identity Politics became, where flinging labels like "fascist", "racist", "sexist" is done all too easily. Also with Twitter becoming an acceptable political discourse medium, try to argue a complex point in 140 characters. You can't! Instead throw a short label in there and you're done. Wipe hands on pants and refresh to see the results.