He may well have said both things. They both make sense. The Democrats definitely lost the Deep South by bringing in civil rights legislation, and that's clear to anyone who has studied the history of USA elections. They also, however, secured the vote of most Black Americans all over the entire nation ever since then for the same reason. So you can say either thing, and it's true, and it has been of some advantage to both the Democrats and the Republicans, but in very different ways. Political parties play these games all the time, playing off one community or region against another. The Democrats and Republicans have basically reversed their regional dominance like a mirror image during the years from the Civil War to now...but the regions themselves have remained very similar in their original cultural character all the way along.

This indicates that you can't trust political parties... :D And I already knew that.

The same general cultural group of people who vote Democratic now voted Republican in 1860...and they elected Lincoln. Parties change. Cultural and regional attitudes and prejudices just go on and on. The USA has always been a house divided...and it's been divided by regions and cultural groupings. The most bitter foes in the USA have always been the Deep Southerners and the "Yankees" in the industrial Northeast...and that continues to this day. The Civil War isn't actually over yet, psychologically speaking, and it may never be.