Most midwesterners' historical consciousness about race relations begins with, and is grounded by, 1960s white flight from Detroit, Cleveland etc., meaning it's (1) recent, (2) urban, (3) middle class, and (4) migration-driven.
All four have significant bearing here.
The fact that the Second KKK in the 1920s—which, at 5 million members was by far the most powerful iteration of the Klan—had 75% of its members outside the South, with 40% being from the industrial midwest, is something that lends credence to some of
@IVMiles's recent points.