I found that as long as you talk about faith issues, they believe they still have a chance to suck you back into the fold. That seems their only purpose in life. I also found that they have answers to almost every question that you throw at them. If not, they call the 1-800 help line. The one question I asked was actually a comment. I asked him that if all human life came from Adam and Eve, then there was some serious incest. Could you please comment. He could find no explanation. I also asked him about why so many differences in the races around the world. He babbled something about genetic defects. I said that it appeared then that God made mistakes. His response was to forget I even asked the questions.
Therefore I believe a discussion with them is futile.
I suppose you should just talk only about issues not related to the cult and ignore all the "borg" stuff.