Frenchy:
These have been convinced that there is a truth and having been so close to it makes them want it even more. It was a notion so deeply ingrained in a heart yearning so much for it that it will not go away.
Good points; Saying, thinking, and believing "the Truth" mantra countless times as a Witness doesn't mean the concept disappears the hour we no longer see ourselves as JWs. Some might continue believing "the Truth" notion years after leaving; perhaps taking it to their graves.
By itself, there is nothing wrong believing "the Truth" is out there. It becomes dysfunctional when one believes they've found it, and condemns, criticizes, and shuns others who don't share the identical belief. Religiously speaking, "the Truth" cannot be proven; it still comes down to a belief system someone cooked up, and followers believe (sometimes by force).
It's a societal norm for most of us to believe in God, and if that's true, He surely has a plan for doing something with us--otherwise, why are we here? Yet, if we grew up in part of the world that believes God lives in all people, all animals, and in everything else (like trees and rocks), then our spiritual quest for truth has a different twist. Instead of looking to answers from a higher power, this belief system sees God in all things. Seeing "the Truth" coming down from the mountain is a foreign concept to them, as their concept of truth is foreign to us. Thus the question, what is truth?
The idea of finding religious truth reminds me of the saying, "Look out what you pray for; you might get it." I found "the Truth" for many years--God help the next one who finds it.