It goes both ways - people flag legitimate claims of conspiracy and dunk on them, too. For example in the 40s, the idea that cigarette manufacturers were conspiring with the medical industry. Or as a 2010s example, that the NSA is secretly recording everything we are doing and saying online (PRISM).
My biggest take-away is that you need to be paying attention, you need to get your news from multiple sources, and it helps to have strong foundational knowledge that you can use to gauge the reliability of those sources. Usually the establishment is right, but sometimes that random guy on the internet is right, so it's important not to discredit anyone solely based on their pedigree. A process that, obviously, the kool-aid drinkers in that subreddit didn't seem to have a grasp on.
Was this actually dismissed at the time as a conspiracy theory? Similarly, claims about the NSA monitoring US citizens were taken seriously well before the PRISM disclosures -- there were hearings on ECHELON in the '80s.
These are seemingly intelligent people that would recognize this same problem in other peoples conspiracy theories and willingly ignorant beliefs.
At this point what is there to possibly do? It doesn't seem like a good idea to bring it up at this point and be like "I told you so" and just get them mad. I hope they have recognized their mistake by now on their own.
Throughout the whole video I'm reminded of the Game Designer’s Analysis Of QAnon[2], where people are thrilled about connecting dots and finding hints where there are none intended.
To delve into politics, there are also many unhinged who put their hope of a better life, some of them probably did so first into Obama (Obama himself has said in his post-presidency book, he found it worrying when running in 2008 that people were putting their dreams and hopes into him), and some of them, when they found their lives hadn't gotten better in 2016, probably thought "Well, Hillary will be more of the similar, and Trump promises greatness (again), what the hell do I have to gain for voting 'similar', and what the hell do I have to lose for voting 'greatness (again)'?". In some sense Bernie also offered that radical change, but if you want to blame brown, gays, etc, people for your suffering, Trump was the easier choice. And rather than admit that they've been conned, they'd rather invent a million scenarios why Trump was (and is) the correct choice, there's just some deep state conspiracy ensuring the continued enslavement of the poor (Note: I don't share this viewpoint, just summarizing it!).
[1] https://youtu.be/5pYeoZaoWrA?t=8067 [2] https://medium.com/curiouserinstitute/a-game-designers-analy...