How did the attack on Pearl Harbor create anti-Japanese feelings?

The novel provides a good answer to this question. After the Japanese attack on Pearl Harbor, a United States navy base, the narrator Jeanne reports that the American government was suddenly fearful of Japanese people who owned commercial fishing licenses (or even radios). Through its FBI agents, the United States government began taking these men into custody for questioning and detention. Though it seems outlandish now, at the time, Americans were afraid that Japanese people living in the United States would display their loyalty to the Japanese emperor and would sabotage the war effort by communicating with enemy Japanese ships or planes.

Japanese-born men like Jeanne's father were suddenly perceived with suspicion by American citizens, who viewed them as men "with no rights who looked exactly like the enemy." Even Japanese-American children born here, like Jeanne, were treated with icy reserve by American citizens: the young girl's teacher maintained a cold distance from Jeanne, refusing to help her or even speak with her when Jeanne was struggling to keep up with her schoolwork.

In Chapter 2, the narrator explains all this hostility directly: "Tolerance had turned to distrust and irrational fear." She describes how her older siblings heard about attacks on Japanese homes and public violent eruptions toward Japanese citizens.

In short, the Japanese attack on American soil caused American citizens to extend a deep distrust and hostility toward United States residents of Japanese descent.