The central objection to the movie is neatly summed up by Weiseltier:
...the film is afraid of itself. It is soaked in the sweat of its idea of evenhandedness. Palestinians murder, Israelis murder. Palestinians show evidence of a conscience, Israelis show evidence of a conscience. Palestinians suppress their scruples, Israelis suppress their scruples. Palestinians make little speeches about home and blood and soil, Israelis make little speeches about home and blood and soil. Palestinians kill innocents, Israelis kill innocents.The problem, I think, is this: Zionists of a certain age and generation think of the Arabs as cartoon villains, with greased mustaches and diabolical plans. To them, Palestinians are symbols, not people. And this tendency to simplify, to rob people of their humanity, cuts both ways: The IDF and Mossad, in their eyes, are flawless, and faultless, the just and glorious warriors.
So I can understand why a movie that tells a different story, and shows how people are often more alike than different*, might be something of a shock to their delicate systems.
[*Please note: In this post, I am not passing judgment on the conflict or the movie. The movie might be awful. Arabs might really be James Bond-style villains, and every single Israeli soldier might be Dudley-Do-Right, alive and in the flesh. I am not contesting any of that. I am simply trying to explain why the movie, if it does what Brooks and Weilseltier say it does, is likely to be upsetting to Zionists of a certain age and generation.]