The article starts with a wrong position. "Fake news" was not invented by Trump, but it was introduced during the election by "PropOrNot". The website, which is probably propaganda by itself, stated that many independent media were Russian propaganda. This unfounded claim was used to help the democratic candidate, after wikileaks published material about pay-to-play and media-bias.
Afterwards the russian propaganda idea was fake news, because there has been no evidence that the election has been strongly manipulated by Russian bots or operatives. Instead researchers find people who have strong opinions and have lots of time to post stuff.
The article has a good point: "If you are convinced that some claim is true, ask yourself why. Is it because you have credible evidence that the claim is true, or is it just because you’ve encountered the claim over and over?" In this I see the media repeating the "Russian hacked the election" thing, for which there is no real evidence. The reports from all agencies only based this idea on rumours. The wikileak documents themselves seem to be downloaded on a USB drive, and not via the internetz. But can we withstand this "fake news", when there is so much support for it? And why is no-one talking about the pay-to-play problem. It is likely a problem of the political system, not just a candidate.
I agree with the solution against fake news. We should have credible evidence. But these should not be "public service announcements". These are usually linked to sponsors or political parties. Most people already disagree on what sources can be trusted. For example I trust wikileaks a lot more than many other people. They stand for freedom of information, unlike their opposition who likes to destroy relevant information (like torture records or emails).
And freedom of information is exactly what is needed for this whole problem. No information should be hidden in a democracy. And that is how we really should solve the fake news /propaganda problem: All relevant information should be available.
Just like every experiment should be repeatable in science.