I think it is the ego that motivates them.  For many of the old timers this has been their whole life for as long as they can remember.  It is their one big achievement in life and they pride themselves on their knowledge (as far as you can call it knowledge).  Since their sense of 'self' is all wrapped up in the lifestyle, to hear anything that might suggest that their course in life has been wrong is like an attack on their person.  Forget Jehovah and Jesus!  They can't even begin to go to the place where logical information and facts can be addressed because it's too much like a personal attack on their intelligence and reason for living.   Like Rawe said, they're pretty much as deluded as any of the other R & F member but I personally do believe that ego and pride are a big part of their stubborn resistance to admitting the very real problems within the organization.  It took a tremendous amount of true humility for Ray Franz to come to terms with and admit to the errors in an organization that he gave the better part of his life to.  Those GB members today have far more ego and pride than they have humility as far as I can see. 

Only those who will risk going too far can possibly find out how far one can go.

t.s.eliot