This:
I think that a lot of JWs feel that the claims can be backed up, but that they personally are unable to back them up.They probably think that a GB member or a Bethelite or a CO or a super elder could back them up. JWs of this particular type think that JW higher-ups are so much smarter than they are that they just accept what these higher-ups say and assume the higher-ups can back up what they say.
and this:
As to why they won't admit they don't know... well, I don't know. I think it's a combination of stupidity, stubbornness, and pride. Also, I think it's fear. They might have some nagging doubts that they suppress. They are terrified of the implications of these doubts, so they keep them locked away. To admit they don't know might, to them, be sort of like letting their doubts out.
I think you've hit the nail on the head. Once, a simpleton Elder told me: "Brother Eden, you're too intelligent for your own good. Don't let your intelectuality derail you from the truth. The GB has done all the research for us, there's no need for you to research anything else. They've prepared all the pap ready for us, you just can't better it or find out things they haven't figured out yet".
Eden