What is Zachary Woolfe talking about?

In his review of the LA Phil's Don Giovanni, he writes, "silence greeted Mozart’s winking quotation of his own “Nozze di Figaro” during the final scene. It was an opera in-joke in search of an opera audience."


At the performance I attended, the audience giggled at the reference.  Perhaps New Yorkers can't imagine that the city that attracted Schoenberg, Mann and Faulkner can have a subtle sense of humor.