I completely understand what you are saying and agree. For example, if I visited your door and you told me that you were not interested because you were an atheist I would not ever reproach you, but I might ask a question such as "Have you always been an atheist, or did you once believe there was a God?" This isn't intended to be confrontational but is just motivated by curiosity on my part.

Perhaps if you were willing to talk about your beliefs I might go on to other questions such as "Do you believe that it is possible for us to determine if a God exists?" or "Do you think it is possible to find evidence that God exists?" and "Would you be willing to listen to some reasons why I feel that there is a God?"

If so we could discuss each individual reason. Really it is comparable to having a discussion here on Hacker News. There are disagreements here on HN but as long as everyone sticks to the guidelines everyone involved can have a productive conversation. I feel that likewise it is possible to have a productive conversation about religion.

Jehovah's Witnesses do have a vetting approach of sorts when it comes to determining capability but as I'm sure you will agree vetting is an extremely hard problem to tackle both accurately and fairly.