Hey, another idea just popped into my mind!
Suppose a worldly (me) used to talk to the JW's who came to his door, and got that particular Watchtower about "The Generation that will not pass away". I mean, the worldly knew that the generation teaching was supposed to mean that a group of people wouldn't die before the end of this system of things came. Now, fast forward to the future, and this same worldly man is told that the generation thing doesn't really mean what that magazine said it meant, and, instead, Jehovah has given new light and now "the generation" means "many overlapping generations". Suppose the worldly man very well remembers having received that magazine, and goes "Hey, something is wrong here! This isn't what you told me before!". And suppose that is the very reason why the worldly refuses the new light. Will Jehovah hold it against the worldly, since it was Jehovah himself who changed his mind and stumbled this guy?