Modestly informed people also know that "the country's two parties underwent a realignment a half-century ago that was precipitated by the Democratic Party's decision, at long last, to champion the equal rights of African Americans and use the power of the federal government once and for all to break the power of white supremacy (backed up law and enforced by terrorism) in the South." 

"This shift is the primary reason why black Americans still vote overwhelmingly for the Democrats while the (majority white) South supports the Republican Party, which began actively courting white Southerners the moment they began to feel alienated from the Democrats for opposing segregation."

It's more important to judge parties by what they stand for today, not what they stood for in the 19th century. What you're doing is akin to blaming a person living today for something their great-great grandfather did. Focus on the here and now. Which party supports civil rights today? Which attracts racists?