Hateful graffiti — including swastikas and the words “Hail Hitler” — were scrawled near lockers inside Hillside High School in Queens, nine months before 400 teens rioted against a Jewish teacher because she went to a pro-Israel rally. The sickening vandalism was discovered on Feb. 15, but school administrators dragged their feet on removing and reporting it, staffers told The Post. “It was immediately brought to the principal’s attention and he did nothing about it,” a faculty member said. With it still up the next day, worried staffers called outside colleagues, resulting in complaints being filed with the NYPD and...