I'm really glad you brought this topic up. I personally have heard that question asked of one self on a few occasions. The one I recall most, was a 'friend' of mine.
He was having a discussion with my mom while we were out preaching. He felt that he would never have become a witness had his mother not raised him as one.
My mom put a lot of energy into trying to convince him that he would have become a witness even if his family hadn't raised him as one. In the end he gave in to my
mother's 'reasoning'(not that anything she said was reasonable) A few years ago I told my mom the same thing, that I would NEVER have become a witness had I not
been raised as one. My mom didn't put much effort into trying to convince me otherwise,, but then again, I've never been easily influenced like my friend was.
In my opinion, when a j-dub makes that statement, I believe what we are seeing is their doubts and questions beginning to surface and this is how it is expressed.