IME, this is how most not-directly-impactful knowledge is used by people. I've been in countless such situations, and it's painful for people with stronger affinity to truth. Unfortunately, under the guise of "good manners", society teaches you to shut up.
We shouldn't avoid debate. We just need to ensure that people debating are there to discover the truth, and not just pick up morsels to share at dinner parties.
If I hear something that seems right and I start repeating it, I generally try to go check if I am talking rubbish or not. If I find out that I am, I stop repeating the thing, or I include the truth next to the story, if the story is entertaining enough in and of itself. I tried to explain why I do this, while having a recent discussion with a visitor about the Navy vs Lighthouse story - https://en.wikipedia.org/wiki/Lighthouse_and_naval_vessel_ur... and was told that what I was doing was anti-social and that I wasn't helping anyone by being interested in the truth of things that people have said. I tried to explain that I was doing it to satisfy my own curiosity for the main part, and this completely floored them. They could not understand the motivation of being personally interested in the reality of a story, for them the only value was if they liked the story.
So in the end, this stuff gets largely uncorrected.
I have long found the fact that 'trying to be smart' is an insult in our society, to be a source of both bewilderment and depression. I remember being utterly confused when even the teachers would use it at school. I'd ask them why we were at school, if we were not trying to be smart? Which would then get me into trouble, presumably for trying to be smart.
After a while I got bitter about this and my response turned into; 'Yes I am. Tell me, how is trying to be thick working out for you?', which still got me into trouble, but with more entertaining results.
Note however that in both cases they (and generally all humans, to some extent) care about their relative status; in most circumstances (especially when in a group), correcting someone will be seen as an attempt to diminish their social status.
It's unfortunate that this is the case, and a lot of people who honestly value being correct have to struggle with getting the handle on this whole status mechanism. I'm not even blaming most people that much here; I do my best to always accept corrections well, and I still at times feel bad or get angry when someone points out that I'm talking nonsense.
In the moment, I can be very combatative and do not tend to fold easy, but if someone demonstrates to me conclusively that I am talking utter bollocks, I appreciate that I have learned something and I try to remember to thank them.
Am from the UK and I have heard that story for years from a variety of people who do seem to completely believe it, as it is usually brought up to give an example that shows Americans being stupid, and the motive of 'aren't we better' would not be there if they thought that the story was false. I didn't know the truth of it but thought it was a funny story, so had gone to look it up a while back.
Is also usually brought up by the same people who will crow about Americans not understanding the concept of irony or sarcarsm, again to demonstrate the supposed superiority of UK culture. I have taken to pointing out that saying that tells me nothing about Americans, but does demonstrate that the person I am talking to presumably never reads any books.
https://en.wikipedia.org/wiki/Rationale_for_the_Iraq_War
"As Secretary of State Powell summarized in his February 5, 2003 presentation to the U.N. Security Council, "the facts and Iraq's behavior show that Saddam Hussein and his regime are concealing their efforts to produce more weapons of mass destruction."[34] On February 11, 2003, FBI Director Robert Mueller testified to Congress that "Iraq has moved to the top of my list. As we previously briefed this Committee, Iraq's weapons of mass destruction program poses a clear threat to our national security, a threat that will certainly increase in the event of future military action against Iraq. Baghdad has the capability and, we presume, the will to use biological, chemical, or radiological weapons against US domestic targets in the event of a US invasion."[35][36] On April 10, 2003, White House press secretary Ari Fleischer reiterated that, "But make no mistake—as I said earlier—we have high confidence that they have weapons of mass destruction. That is what this war was about and it is about. And we have high confidence it will be found."[37] Despite the Bush Administration's consistent assertion that Iraqi weapons programs justified an invasion, former Deputy Secretary of Defense Paul Wolfowitz later cast doubt on the Administration's conviction behind this rationale by saying in a May 2003 interview: "For bureaucratic reasons, we settled on one issue—weapons of mass destruction—because it was the one reason everyone could agree on."[38]"
"After the invasion, despite an exhaustive search led by the Iraq Survey Group involving a more than 1,400 member team, no evidence of Iraqi weapons programs was found. On the contrary, the investigation concluded that Iraq had destroyed all major stockpiles of weapons of mass destructions and ceased production in 1991 when sanctions were imposed.[39][40][41] The failure to find evidence of Iraqi weapons programs following the invasion led to considerable controversy in the United States and worldwide, including claims by critics of the war that the Bush and Blair Administrations deliberately manipulated and misused intelligence to push for an invasion. "
I wonder what kind of mischief these fellows are up to these days, or have they all retired?
So, someone spouts a well researched conspiracy and others engage in a conversation and the person gets to recite their well prepared talking points. That feels good to the person, that's positive reinforcement. That's a story they can take to their online echo chamber for even more positive feedback.
They hold on to the conspiracy as something to talk about, and as something they can feel superior about.
So should we just avoid debate? That doesn't seem right.