I was ignorant rather than gullible. I left school at sixteen so had very little education. We had two books in our house apart from the JW literature, Jane Eyre and The Water Babies. There was no money for books, we were dirt poor. We did have library tickets and borrowed books but it was only a little village library. My parents didnt buy national newspapers. The internet didn't exist.
I knew nothing about anything but I was intelligent so I worked it out eventually and left at thirty. This is why the cult targets ignorant, poor people, especially in developing countries. It's so easy to make fun of evolution to such people when they know nothing. So easy to say the bible is historically accurate because Babylon, The Hittites and Ur have been discovered. Although I have to say I did worry about that, I knew it didn't necessarily mean the rest of it was true.
I will say this, I followed my belief system from the heart and lived it. I didn't do it to please anyone else and I really believed I was saving lives in FS. I am genuine and not a hypocrite and there is something to be said for that. I believe it's what got me out.