Obama himself tried this approach big time with his first presidential address to the UN General Assembly in 2009. The delegates clapped, and then in 2011 made America the UN’s fourth most-criticized country on the planet for human rights issues. (Number one in the UN’s scrambled universe being Israel, followed by Sudan and Syria.)
So why would any of this be a problem for an ambassador who favors a mea culpa doctrine for America? Because the real world intrudes. Because bad things will come of it. Because the real job of the U.S. at the UN is more often to try to contain the damage and to minimize the waste and corruption, rather than wield the U.S. seat as an active force for good. Override that, and you are riding for a fall. The further question, unfortunately, is how many others might also pay the cost.