I'd show them the UN stuff and ask them what they think about that.
Had my first visit today
I brought up the UN issue once with another Witness but he dismissed it as apostate originated. He totally dismissed any Watchtower responsiblity of wrongdoing. After further debate he accepted that the watchtower has wronged it members but shuffled it off as nitpicking. It was amazing how true this board was when it said that many Watchtower Society members have been duped by the library card explanation.