The union and administrators must have really hated his guts. The union is easily explained; he made other teachers and schools look bad. I wonder why the administrators didn’t want the students succeeding though.
> In his final years at Garfield, Escalante received threats and hate mail.[14] By 1990, he had lost the math department chairmanship. Escalante's math enrichment program had grown to more than 400 students. His class sizes had increased to over 50 students in some cases. That was far beyond the 35 student limit set by the teachers' union, which increased its criticism of Escalante's work.[14] In 1991, the number of Garfield students taking advanced placement examinations in math and other subjects jumped to 570. The same year, citing faculty politics and petty jealousies, Escalante and Jiménez left Garfield.[14] Escalante found new employment at Hiram W. Johnson High School in Sacramento, California. At the height of Escalante's success, Garfield graduates were entering the University of Southern California in such great numbers that they outnumbered all the other high schools in the working-class East Los Angeles region combined.[15] Even students who failed the AP exam often went on to study at California State University, Los Angeles.[14]
> Angelo Villavicencio, one of Escalante's handpicked instructors, took over the program after Escalante's departure, teaching the remaining 107 AP students in two classes over the following year. Sixty-seven of Villavicencio's students went on to take the AP exam and forty-seven passed. The math program's decline at Garfield became apparent following the departure of Escalante, Villavicencio, and other teachers associated with its inception and development. In just a few years, the number of AP calculus students at Garfield who passed their exams dropped by more than 80%. In 1996, Villavicencio contacted Garfield's new principal, Tony Garcia, and offered to come back to help revive the dying calculus program. His offer was rejected.[14]
https://en.m.wikipedia.org/wiki/Jaime_Escalante