"Progressives should not make the same mistake that Ernst Thälmann made in 1932. The leader of the German Communist Party, Thälmann saw mainstream liberals as his enemies, and so the center and left never joined forces against the Nazis. Thälmann famously said that ‘some Nazi trees must not be allowed to overshadow a forest’ of social democrats, whom he sneeringly called ‘social fascists.’
After Adolf Hitler gained power in 1933, Thälmann was arrested. He was shot on Hitler’s orders in Buchenwald concentration camp in 1944."
The centrists were aligned with Hindenburg. Friekorps were just as avid commie-bashers as any National Socialist.
The main problem Ernst had was affiliating himself with the Russian Revolution and advocating for more of the same in Germany. That made him an enemy of nationalists during a period in which “International Jewery” was the boogie man under everyone’s bed.
The idea that he could just strike up common cause with people who wanted him dead is absurd.
Particularly, there was huge overlap in membership between the Freikorps and the Stürmabteilung. So it is important to note that the Freikorps was a direct precursor to the Nazi brownshirts.