A lot of religious folks can have an open-minded discussion about their beliefs without getting defensive. Some can actually consider things from another point of view and point out the validity in the other person's point.
I agree. Let's not overgeneralize all religions and people.
I can't speak for other religions because I don't have that experience from the inside, but I do know how JWs think. The reason JWs cannot do this imo is because their self-righteousness does not allow any openness to being wrong. Their whole self-identity would crumble if they thought that. Remember that the org breeds perfectionism - always trying to attain it (that is the ultimate goal, right? perfect life) Approval from God and others hinges on this very core belief. So it makes complete sense that you would never even toy with the idea of being wrong - there is way too much at stake. And there is the black and white thinking. Either you are with us or you stand against us. Anyone who thinks differently is standing against them and must be convinced or condemned silently.