Flat Earth and on three (Pratchett: four) elephants, the fire of the Inquisition, Nazism... Yes, the crowd can not be wrong. Most accept the opinion that will be imposed on them.
Now a huge number of media systems, which can cleverly manipulate opinion. It is necessary to evaluate everything with a sober mind.
That is why the advetising in media is so expensive, they can manipulate the opinion. But when people see how the cryptocurrency grow they start to trust everything. In 2017 people invested in all the ICO do not see even the site, becase they was affraid to lost the profit, but at the result they lost the money.