People will believe anything if they try hard enough.
History is full of examples of people believing rubbish because they suspended all their rational faculties.
They believed older women in the village could get on their broomsticks and fly.
They believed they would have sex with their pet cats.
They believed that when Stalin told them that communists who had fought with Lenin for the overthrow of the tsar were traitors, those communists were traitors.
They believed that something they had strongly believed five years ago, was rubbish because Comrade Stalin told them it was rubbish.
They believed that it was year zero.
They believed that when Jews in their city were rounded up and put on trains, they were just being taken away to work.
They believed that the gulags were actually really nice places to go, sort of like a rehabilitation centre, doubtless filled with massage parlours where you could go after a healthy hour of breaking up stones (mind you that last one was the Goldsmith's LGBT society, so perhaps they're not representative of most people, however credulous).
In short, people will believe anything they feel there's a social benefit to believing. We are living through one of those frightening periods in history, where adherence to a belief in something everyone knows is a lie, is being demanded by a tiny section of the population who are determined to ensure that our authorities and institutions also demand it, so that people will be too afraid to publicly question it. Because the belief is utterly ludicrous, we don't really believe that it will fly, but it is no more ludicrous than all those other beliefs that flew for a time.
War is peace
Freedom is slavery
Ignorance is strength
Transwomen are women