Wow. A lot of revisionist history here. The KKK was started by Democrats to frighten blacks and the Republicans who freed them. They rose to power again in the early 1900s because of a racist Democrat president, Woodrow Wilson, gave them a voice. He not only praised Birth of A Nation, but also resegregated the Federal government. In 1924, some non-KKK members of the Democrat party wanted to put in a special plank in their platform denouncing their violence. But, there were so many KKK members in the party it was actually voted down. It flared up again during the Civil Rights movement, again containing mostly Democrats opposed to desegregation. This also led to Jim Crow laws.
It's hilarious to watch people perform some crazy mental gymnastics to alter that history. "Oh no, they're totally an organization of the right. They're just made up of Democrats, and just fought on the side of the left/Democrats for over 100 years, then suddenly switched sides. Which is good because we can attack Republicans with their "long" history with them. Shh, don't mention that Republicans were the targets of many of their attacks and that the Republicans have always been opposed to them. For reals." LOL.
Now, it may be fair to say they slowly evolved to a party of neither side, as hatred for minorities pretty much took over their whole platform. But, to try to claim they were ever an organization of the right is just a plain lie. Usually one stated for political purposes, not with any fact behind it.