Deep question.

Sometimes people repeat ideas without sufficient critical thought. That critical thought may well be due to lack of understanding around the subject which limits the ability for the person to review whether it is correct before spreading the information wider.

I think that some of this is because the news that we get from credible sources doesn't explain why they're credible (e.g. no sources). Consequently when we see news in the same form from other venues (which are less credible) they look and appear no different from the credible sources. My proposal here is that news sites should link and quote sources. Example: The Times (UK) quoting the UK Government on lockdown rules. The government web site is actually clearer in many cases, and people don't seem to know where to go to get the actual facts.

(I've not covered bias here either, but that's important).

Another issue that we have is that the experts that are used sometimes don't understand it either! I follow a Doctor (@curexcomplex on twitter) who is an expert immunologist and she often corrects those on news sites. I think that part of this is that when ideas are dumbed down so that a non expert can understand, some of the nuances or subtleties are lost. We can then have 'Chinese whispers' where non-experts then repeat information and the nuance or subtleties are further eroded.

I think that also we have a 'fast' news culture, where there's a level of 'coolness' of spreading news first. I think that means that we don't necessarily check things because we want to share that 'cool' story as fast as possible. I've done this myself and been corrected by peers (who are actually experts in Chemistry (the video was on chemistry) which I'm definitely not!)

Everyone thinks that they're above average. That means that they think that their view is valid. The opinion is equally valid but as a reliable source this is not directly related. For example, unless a Celebrity is a reliable source (a qualification in the subject would give credibility) on immunology we should call them out as such when they talk about vaccinations. For example we could say 'You don't have a high school qualification in Biology. Your credibility in areas relating to biology is therefore less than someone who has a degree in Biology. Your opinion will therefore get a lower weighting by default.'. That doesn't mean that their opinion is less important than anyone else's but their credibility on this subject is worse. I fear that most don't understand this concept. I think this is much like how in history we have primary sources and secondary sources. Maybe we ought to have a way to indicate if the person is a primary source or secondary source.

Lastly, I think that the news sites need to sell ads, so there is and incentive to publish stories quickly and less incentive to take extra time to confirm stories are correct. This is made worse because people have moved on by the time a correction is provided, and it is not shown with the same visibility. That means that the correction is not seen by the same number of people.

(One other thing; I think that folk need to be more humble about learning things when they don't know, and when people are factually wrong we should be happy to say that and to receive it. Obviously this needs adequate supporting evidence.)

Edit: grammar