I don't think much in this regard has changed in human history. Everyone is subject to various biases. It's impossible to know everything. So we use the faculties we have to decide what to believe and that is largely a function of intuition. The problem is that more effort is needed to prove or disprove our own intuition, but because it's ours, it's a big ask.The problem is the people that are going to watch it and then repost it and spread his nonsense don't know any better. They won't actually think about what he is saying. They just jump on a bandwagon and spread it as some sort of truth.
People have certainly shown that they don't have the ability to think things out anymore. Not all people, but it seems like a large chunk of people.