This is just a variant on the "Were the Nazis on the Left or the Right?" The question here is "Which party has a stronger history of racism: Democrats or Republicans?"
Opinions are divided, and people see what they want to see so these discussions usually just result in spinning of wheels.
My own opinion is that the National Socialists had an exclusively Collectivist viewpoint (group identity politics) and cared nothing for Individual rights, so I have to place them on the Left.
Similarly, the Democrats were pushing to keep blacks in their place (through gun control, among other things) from the time before the Civil War, up through their identity as Copperheads (sabotaging the war effort -- gee that sounds familiar) during the war and creating Jim Crow laws and the KKK after the Civil War. George Wallace was a Democrat, Bull Connor was a Democrat. When the Civil Rights Act of 1964 passed, the NAACP gave a special war to one congressman for his hard work: he was a Republican. Martin Luther King was a Republican. Jackie Robinson was a Republican.
But some folks will never buy any of this. Hurricane Katrina happened because Republican George Bush hates black people -- didn't you get the memo?
But as the origanl posters stated that liberals just say: "Oh but the parties switched in 1960. Republicans became Democrats and Democrats became Republicans."
It's libtard "logic" we are dealing with.
The claim of Republicans as supporters of civil rights stems from the Reconstruction era. However, it must be remembered that had Lincoln not been assassinated, he likely would have opposed Reconstruction and permitted the Southern states to re-enter the Union merely upon a loyalty oath. Andrew Johnson, his successor, opposed it as well, but less successfully than Lincoln would have. The GOP abandoned this policy as a compromise to allow the election of Rutherford Hayes in 1876. Northern enthusiasm for bayonet rule of the South waned as its costs increased and the excesses of carpetbagger rule became better known. From 1877 onward, Republicans did little as resurgent Southern whites gradually disenfranchised blacks and reduced them to the status of subjects with few rights.
Does not the fact that the Nazis proclaimed themselves to be collectivist and socialist prove the point? They placed themselves on the left.