How do textbooks shortchange American idealism in the Reconstruction era?

Hopefully these quotes help:

““Since textbooks find it hard to say anything really damaging about white people, their treatments of why Reconstruction failed lack clarity. Triumph presents the end of Reconstruction as a failure of African Americans: “Other northerners grew weary of the problems of black southerners and less willing to help them learn their new roles as citizens.” The American Adventure echoes: “Millions of ex-salves could not be converted in ten years into literate voters, or successful politicians, farmers, and businessmen.” (Pg 160)

“The treatment of Brown, like the treatment of slavery and Reconstruction, has changed in American history textbooks. From 1890 to about 1970, John Brown was insane. Before 1890 he was perfectly sane, and after 1970 he regained his sanity. Since Brown himself did not change after his death, his sanity provides an inadvertent index of the level of white racism in our society.” (pg, 172)