@Aireael I, personally, was not talking about the witch hunts. I’m talking about how easily (some) people in real life are tricked and scammed because they don’t bother checking the facts and just believe what they hear, such as the hundreds if not thousands of people who fall for phishing scams, the people who share bullshit science on facebook and people who believe in hoaxes.
Additionally, the point of my comment was that
in a story, making characters suddenly act stupid for the sake of plot is lazy, boring to read and insulting to readers.
TVTropes explains it quite well in their Idiot Ball and Idiot Plot pages. I suggest looking those up.