Yes, I agree, being rude doesn't help anything, it just confirms their brainwashing that apostates are all evil and bitter. I have talked to many JWs that have come by my house, even when I explicitly state that I am an apostate they continue to talk with me, because I am polite. Nothing much you can say in any encounter will shake them, but if you are rude it gets their back up and causes the cult programing to kick in.
I was reading recently about the amygdala, the primitive part of the brain. This part of your brain is activated when you are in a stressful situation, and it responds much faster than the part of your brain that controls higher level functioning. If you hear gunshots for example, your pulse rate will increase and adrenaline will course through your body and you wil be running away before your higher level brain can determine if the danger is real or not. Obviously this is an evolutionary advantage, as it helps you to run from an immediate threat.
I think what happens with Jehovah's Witnesses is that they have been so thoroughly conditioned to fear apostates that if they are in a situation with someone that is acting in a hostile way, the primitive part of their brain takes over and they become very uncomfortable and afraid. The logical part of the brain is not in control, so nothing you then say will sink in. This is true even if they have doubts themselves, because it takes time being away from the meetings for that fear conditioning to go away.
