I think it is because once somebody "buys into" the false information they now in a sense "own it".
Once they have the faulty information they often spread it to others. Therefore they do not want it to be proven wrong, because they don't want to be proven wrong because that would prove that they have been spreading incorrect, unreliable information. That would mean that they can not be trusted. So, there is a lot pf resistance against correcting the incorrect information.
Once they have the faulty information they often spread it to others. Therefore they do not want it to be proven wrong, because they don't want to be proven wrong because that would prove that they have been spreading incorrect, unreliable information. That would mean that they can not be trusted. So, there is a lot pf resistance against correcting the incorrect information.