Sadly, JWs would rather you trust the words of men instead of the words of Jesus Christ.
I think about that all the time. Heretics were around while the apostles were still alive. Imagine that! In utter disregard for their own life, they were convinced they had the truth.
Some people just have a natural contrarian personality. Psychologists call this ODD (oppositional defiant disorder). These are the kinds of people that say black when you say white. Or, they say "down" if you say "up". Or, if they hear a story, they turn it into a story about themselves.
While this cannot explain all of the reasons people put their trust into men instead of Jesus, I think it explains a lot of JW's.
People also use the mental device known as "suppression". Others, are just straight up gullible and proud of it. They interpret their gullibility as good-heartedness, and being righteous. These are the people who will say, without any investigation, "it has the ring of truth". That's what my dad told me when I asked him why he joined the WT.
The bible just calls them fools.
Pr. 28: 26 - He that trusteth in his own heart is a fool
“But though we, or an angel from heaven, preach any other gospel unto you than that which we have preached unto you, let him be accursed.” - Gal. 1: 8