It's cult mind control at work. She believes that what the Watchtower teaches is the truth, so seeing something that is in conflict with that will arrouse cognitive dissonance. CG is an uncomfortable state, so she has to resolve that, the only way to resolve that is to fall back to the idea that "The Watchtower is the the truth", so your argument must be false, end of story. You will probably never get anywhere by challenging her like that, you are attempting to unwind years of conditioning, you are just causing her to put up her defences. Direct confrontation like that almost never works, in my opinion.
In my experience people break free of this in a couple of ways. One way is that something happens to them that is so extremely painful they are forced to confront the notion that the Watchtower is not the truth. Mistreatment by the elders or a fellow JW or other difficult situations can cause that.
The other is if the person learns critical thinking skills and starts seeing the logical fallacies on their own.
I have seen a few experiences where someone helped a loved one out of the organization, but it was extremely difficult and required a lot of patience. If you want to save your marriage and get your wife out, you need to back off for now. Work on strengthening your marriage for now. Rebuilt that trust and look for ways to get her to learn to think.