"If you tell a lie big enough and tell it frequently enough, people will eventually come to believe it". What is an example of this happening today?
I would really rather that these were actual examples, and not conspiracy theories. We all have our own unsubstantiated ideas about what shadowy no-gooders are doing, but I'd rather hear about things that are actually happening.
People, no matter the inteligence or schooling, are more likely to believe what they hear more often. (If 10 people you know swear that eating mint will keep you from going bald it might just be true)
This makes sense and is normal, at least until the modern world.
Now add social media and an algorithm that its only purpose is to increase clicks/likes/interactions. Suddenly everything everyone is talking about is whatever you clicked on last time. A positive feedback loop occurs. The more videos you look at on the same topic, the more those get served, the more you view them, the more you believe them.
Experiment : Try creating a brand new Google account and watching 3 videos on YouTube on a single topic. Refresh YouTube page, or check back tomorrow.