I used to quarrel over peoples’ sources. Links from sketchy websites, second hand anecdotes, statistics: whenever people would employ these to a persuasive end, I’d point out the unreliability of the source, hence invalidating their point.
I was right. And ineffective.
Fake news didn’t start with the internet. Just ask anyone who’s heard the tale of the fish Young Tom caught or the description of Joe’s girlfriend, who you wouldn’t know because she goes to a different school. The more interesting question for Young Tom and Joe is not “Is it true?” but “What is at stake for you in the story?” Treating a tall tale as an incorrect fact misses the point; it’s a story about the person telling it, and it should be handled according to the conventions of narrative, not forensics.