Terry -
Nailed it again!
I very recently had a discussion, (both written and verbal), with a an old JW friend, where I used the same argument, (although not nearly as eloquent and concise as yours), to make the point about the uselessness of arguing scripture or doctrine. In the end, her cognitive dissonance kicked in, but I believe that was only because the point was made clear to her.
I could not agree more that it is not only a waste of time to debate interpretation based on a false premise, but also tends to prove to be counterproductive in the end due to the dishonest and unfactual nature of the content of the discussion.
I will write more about this on a separate thread shortly. I am still a bit raw over the outcome with the specific friend, (someone whom I care about quite a bit).
d4g