The question is who gets to decide on what is mis or dis information?
Just because something goes against the popular or accepted narrative does not mean it is wrong.
In media outlets with published standards, journalists (and editors of their work) make those calls every day while seeking to present facts in their reporting, or checking facts while editing columns and op-eds.
But in the end it's the individual who must apply critical thinking to try to know what is factual.
There is also a level of trust implied, since most of us are not experts in more than one or two fields of knowledge, at best. Apparently right now that's a big problem: we're not expert at most things, but we don't trust anybody else including actual experts either.
Trump aimed for us to trust only him. Most of us didn't ever trust him, since he racked up so many easily certifiable lies, but he did convince a lot of people not to trust anyone else either. A very damaging effort, and outcome. Could take a long time to recover from it.
But for purposes of exposition of facts. the decision on what's factual is usually arrived at via consensus... typically a panel of experts on the particular topic for a TV show, or "three credible sources" for a point in a news article, etc. Sometimes they're wrong, and get called out on it, and have to publish corrections.
This process including corrections is not always as complicated or time consuming as some would like to make it. In the era of social media especially, request for factual correction can pop into a newspaper's in-box in a matter of minutes, and get made within the hour. In reviews of articles in professional journals, of course corrections can take longer. And then we have evolution of scientific explanations of the physical world we live in, making and testing hypotheses, filling in the gaps. Some of that stuff has taken centuries already. Advances are fast enough in life sciences though that almost everything I learned about cell biology 30 years ago is likely wrong.
If Facebook wants to be a curator of news, maybe they need to poach some people away from a place with those standards I mentioned in opening this post. Reuters, the AP, any mainstream newspaper....
But, I'll concede that being factual is not usually a priority for propaganda artists, nor for miscreants who just want to throw a spanner into the wheels for the hell of it (aka trolls). The former, if they are expert, are often aware of facts but specialize in minimizing the impact of a set of facts by use of language that offers some other desired and compelling context. As for trolls, well they can have a variety of purposes including just killing time but it doesn't make them less dangerous sometimes.
How to regulate speech by propagandists and miscreants? In the end it's best done as a community effort. That can be uneven but it happens all the time. Community standards do tend to point to a consensus on particular issues. They may not be the same all over the place, either, just as views on politics differ from one place to another. But you can find examples of it all over social media if you sift through the posts. Sure there are threads filled with echo chamber BS. But there are also threads filled with posts from people citing facts from credible sources, offering their own professional expertise in support of someone else's critique of a dodgy-looking assertion made by yet someone else, etc.
Researchers have come up with data on certain types of misinformation, and discovered that a lot of it is sourced to a surprisingly small number of individuals. Vaccine hoax material was largely sourced to only a dozen people, and yet it has been all over the net... but when that was reported, Facebook did take those accounts down. So it's not impossible for disinformation to be mitigated by whoever owns a venue although the data behind the misinfo might be collected and presented by other entities.
The majority of false claims about COVID-19 vaccines on social media trace back to just a handful of influential figures. So why don't the companies just shut them down?
www.npr.org