But then where do you draw the line? Is a work of fiction "misinformation" because it portrays something that does not exist, or does it get a pass because it's explicitly labelled as fiction?
It gets a pass because it does not purport to be the truth.
How about religion? Most religions describe all powerful deities and scientifically unexplainable miracles, none of which can be proven. Do we class religious teaching as misinformation too?
When religious teachings are limited to the existence of creator beings and deities and things that you can't see or interact with, no. They're just mythology. When they are limited to how you should behave at a high level, no. They're just philosophy. There are bright lines, though, like telling people how to vote, where religion stops being religion and starts being a political organization under the guise of religion, and that's not okay.
It also starts to become very grey when religious leaders advocate things like vaccine refusal, because that can cause public health crises, like the rather alarming measles outbreak in Texas. I would argue that doing so is crossing a line, because as was proven in that case, even the relative isolation of a religious community is not adequate to prevent a lack of vaccinations from causing a major public health crisis across multiple counties.
Then there are other cases. Consider new research that contradicts previously established research? This happens all the time as science advances. Should a scientist's new theory be immediately discredited without giving it an opportunity for peer review and further research simply because it seeks to disprove some earlier research?
Depends. If the scientist's theory provides robust evidence, was authored by someone without a history of publishing fake papers and who has no ties to anyone with such a history, uses math and research methodologies appropriately, and has been published in a peer-reviewed journal that is appropriate for the subject area, then it should be followed up with additional studies to figure out why there is a conflict between the previous studies.
If the scientist's theory provides little more than a different way to manipulate the numbers from other studies (metaanalysis) in ways that contradict scientific consensus, with no new data, was authored by or edited by someone who has authored multiple similar papers that attempt to push a similar viewpoint, is filled with blatant methodology errors that should be obvious to a second-year college student in the sciences or social sciences, and is a medical article published in a physics journal, it should be immediately discredited as complete and utter garbage.
There is a point in the middle beyond which it makes no sense to give something the benefit of the doubt.
When a scientist is repeatedly falsifying information or repeatedly using poor scientific practices with obvious methodology errors or misunderstanding the basic science of what they're talking about while writing a paper filled with pseudoscientific bulls**t in a way intended to fool lay people who don't understand the science into believing it, that's disinformation.
When a journalist reads such a paper and promotes it as proof that their preexisting opinion was right all along, that's disinformation. When this is further fueled and amplified by professional chaos mongers in Russian troll farms, that's disinformation.
Finally, if the "proof" of something is published only in a YouTube video or similar, that one factor by itself is enough to guarantee that it is garbage without even considering any of the other factors above, because it means what they are saying is so obviously false that if someone read it on paper, they would immediately call the author a moron, but they're hiding that tiny bit of dubious information, spread across a one-hour video, because baiting the audience will get more views on their channel.
Science needs healthy debate, it needs people to challenge established facts either to prove or disprove them.
It does. But the key word here is *healthy*. And part of that requires everyone involved in the conversation having a proper understanding that the vast majority of papers that go against the status quo turn out to be incorrect, either because of methodology mistakes (honest) or because of falsified data (fraud). As long as the folks reading the papers read it with a healthy skepticism, it's fine.
Where it becomes a problem is when a few researchers repeatedly and intentionally create multiple similar dissenting papers with similar flaws, getting retraction after retraction, in an apparent effort to mislead, and then people latch onto those papers as truth and ignore the retractions after major flaws are pointed out, or worse see the retractions as proof of some kind of conspiracy to hide the truth.
Where it becomes disinformation is when people start cherry-picking those dissenting papers, ignoring the mountain of evidence that contradicts those papers, and using only the cherry-picked papers to claim that their fringe viewpoint is the truth and everyone else is wrong. And unfortunately, a certain subset of the media, influencers, etc. were very much doing that, and it got out of control.
That's not healthy debate. That's Fox News and one side shouting over the other, reinforcing people's preconceived notions. That's the opposite of healthy debate, and resulted in people being the opposite of healthy, which is to say, dead from COVID.