If you want to prove the point to someone just ask them to accompany you as you take some outside research on any subject that JWs believe to any JW and ask them about it. Better yet take outside research to the hall and watch what happens when you try to use it in a comment.
Wt are smart enough to to never say "never do this" or "don't ever do that" so newer literature will be ambiguous and general, making it difficult to prove outright.