It sounded like he is a very pragmatic individual and calls it like he sees it. What is the problem here? Every nation works through the UN when it is in that nations interest. The UN is not a government, it is not a sovreign state, it is (was) a place for sovreign states to discuss and hopefully work out problems. No sovreign state is going to willingly surrender their self interest just because the UN has a differing opinion.
One other point, is that if he is selected for the position it will be his job to represent the United Statesd interest to the UN, not represent the UN's interest to the United States.