I find it to be similar to how people describe prayer. If you pray for something and it happened, your prayer was answered. If you pray for something and it did not happen, your prayer was still answered. Maybe nothing happened because god is teaching you patience. Maybe something different happened because that is what god saw as the best outcome for you. Maybe you got the opposite because god needed you to learn a lesson. And so on. No matter the outcome, prayer worked.
So the GB will say the same about god's influence on their decisions and statements. It may have been wrong, but it was the right thing to do/say at that time, proving that it was god's guidance. It may have been wrong, but it led to people acting in a way that helped grow the organization, proving that god was guiding them. And so on. Russell or Rutherford once used that misdirection to claim that something they got wrong was good, because it led to a culling of those whose spirituality was weak. That's an insane thing to say about people you were supposed to be saving! But if it got them off the hook, it was good enough.
I've said it before- the most effective liars lie to themselves the most.