The answer I would expect:
If you are referring to the Governing Body, they can't make a mistake, because the term only applies when they are acting as a group with holy spirit, so this shields them as individuals.
But as individuals they can make mistakes, but as individuals they don’t run the organization.
Interestingly the Mormons have a relatable moniker.
As a group they think they really are prophets, so when something has to change they blame the individual and say “he was speaking as a man” and this somehow covers over everything.