Remember that jw memories only extend as far back as the actual witness themself. An old teaching that was changed long before someone joined but hasn't changed during their membership - hasn't changed in their opinion.
Then, when you do convince a dub that changes happen all the time and not much is firmly fixed, they are proud of that and see it as a good thing.
No winning with a dub.
sort of like this argument from my wife: I say world is terrible and bad- she says four horseman and end times signs armageddon right around the corner; I say world is better and safer - she says peace and security therefore armageddon right around the corner.