He didn't say Republicans... he said Conservatives. At the time of the Civil Rights movement, most of the aforementioned bigots and simple-minded human detritus were southern members of the Democratic party known as "Dixiecrats".

Equating all liberals as Democrats and all Republicans as conservatives is a fairly recent phenomenon. Especially considering that 2 of our most famously progressive presidents, Abraham Lincoln and Theodore Roosevelt were members of the Republican party... and two of our most racially bigoted Senators, Jesse Helms and Strom Thurmond were both Democrats initially.

Social conservatives ARE the reason we still are where we are in this country... and the quicker we can have them sterilized so they can't breed anymore... the better!