As far as I could tell, there were no protesters in the vicinity of Lincoln Center on Nov. 15 before a Saturday matinee, the final performance of “The Death of Klinghoffer” at the Metropolitan Opera. This was a big change from the opening night of the Met’s season in September and the premiere of the “Klinghoffer” production last month, when hundreds of angry demonstrators gathered to denounce this opera by the composer John Adams and the librettist Alice Goodman as an anti-Semitic work that dared to humanize terrorists. Of course, Saturday is the Jewish Sabbath. But the only sign I saw being held outside the Met at the sold-out matinee said, “I need a ticket!” in big red letters.This was also to have been the day of a live HD simulcast of “Klinghoffer.” But Peter Gelb, the Met’s general manager, canceled the broadcast, bowing to pressure from the Anti-Defamation League, whose leaders were concerned about the work’s gaining international exposure at a time of a rise in anti-Semitic actions.