Elders, for example, through JCs are privied to info about the JW involvement with the UN, 607 bce, etc, etc...
people who actually do study a lot, you think they figured it out???
That is exactly how it all fell apart for us. My hubby was the WT overseer and a diligent Bible student. He thoroughly studied in preparation for the WT study and would often share with me things he said just didn't fit. "the Bible isn't saying that" he would tell me. Sometimes he said "I just cannot get up there and teach this". But he would, and gloss over the things he didn't agree with.
I studied a lot too, but was so indoctrinated that it took him showing me things for several years before it really started to erode my faith.