Here's a low ranking in which South Dakota can find relief: South Dakota is among states with low participation in the white-supremacist hate forum Stromfront.
Stephens-Davidowitz found 12 South Dakotans participating in Stormfront's particularly vile community of loathing of "the other." According to his data, South Dakota ranks 34th per capita, below the national average, on this metric. Nebraska has the lowest per-capita Stormfrontery in the area, with a ranking of 44th for the 18 profiles Stephens-Davidowitz found.
Stephens-Davidowitz, who writes for the New York Times and wields a Ph.D. in economics from Harvard, offers one other bit of hopeful data about South Dakota's online racism. In a 2013 paper, Stephens-Davidowitz found that South Dakota ranked 40th among states for Google searches including the n-word. Wyomingians, Minnesotans, and, interestingly, Stormfront-avid Montanans searched that term even less than South Dakotans.
I wonder: is casual Googling among the broader population a stronger indicator of racial animus than active participation in an online hate group? If we're feeling hopeful, let's interpret the Montana data as a demonstration that Stormfront is a fringe element with little impact on overall statewide characteristics, kind of like South Dakota's Constitution Party.