Chattanooga and Hamilton County, Tennessee were never hard core Confederate or entirely Southern Democrat. The city and county are located in East Tennessee, which had many Union sympathizers during the Civil War. After the war, Hamilton County was competitive between the Republicans and Democrats, with the only major break being 16 years of Democratic victories between 1932 and 1948, when Roosevelt and Truman won, due to the Depression and the generous aid to the area from the Tennessee Valley Authority. Since 1952, the Republicans have won every Presidential election except 1968, when George Wallace, an independent, won. These victories included years when two Southerners, Jimmy Carter and Bill Clinton, ran as the Democratic nominee. But Hamilton County remains competitive, with Trump beating Biden by 10 percentage points.
I don't know what Samuel Jackson's actual experience was, but suffice it to say he did not grow up in a hard core white supremacist area.