Using his own logic, isn't he saying (at least implying) that JW's are proved to be Jesus' true disciples (the "B" in the causality model) becausethey are "preaching the good news" (the "A" in the causality model). He states this but presents no facts as to the truth of the statements, presents no evidence, and then wants to walk away from the discussion. I do believe he is really into 'labeling'.
He has also assumed that since the early Christians preached the "Good news" and since JW's preach the "Good news" :
What JW's preach = What the early Christians preached
Which does not necessarily follow at all. It's just more equivocation implicit in the argument, but unproven.
Perhaps he read a few (maybe dozens) of books on intellectualism and "now he are one" (sorry, this sounds like a label doesn't it?).
I've noticed (During the course of the last dozen years) that internet JW's are notorious for committing the same logical fallacies they accuse others of. I think the problem is no one ever becomes good at avoiding logical fallacies until they learn to suspend their own beliefs entirely. Logical arguments constructed for the express purpose of supporting preconceived notions almost always have problems.