The Anti-Defamation League is facing backlash over what its critics have called unwarranted hostility toward Mayor-elect Zohran Mamdani, after the organization publicized a website and related tip line to monitor his administration for actions that could be construed as antisemitic. The announcement of the initiative came after a closing stretch of the mayoral campaign during which Mr. Mamdani’s detractors, including Jonathan Greenblatt, the chief executive of the A.D.L., repeatedly accused him of antisemitism, a charge he has strongly rejected. It is the latest in a series of controversial moves by the organization, which was founded in 1913 to fight antisemitism...