There have been reports of demonstrators chanting Hamas slogans, of synagogues being defaced with swastikas and anti-Jewish hatred being posted on the internet. There also has been, across the U.S., a spike in antisemitic incidents since the war in Gaza erupted on Oct. 7 after the militant Palestinian group Hamas launched a bloody surprise attack on Israel, experts said. But for a New York City professor who experienced antisemitism firsthand as a 10-year-old girl in Poland, it was reports of Jewish students being harassed on campus that chilled her to the bone. Maria Haberfeld, who teaches at John Jay College...