It's interesting that you mention the KPD, one of the founders Rosa Luxemburgs most famous quote is "Freedom is always, and exclusively, freedom for the one who thinks differently." it should also be pointed out that she was killed by freikorps, who were also used by the "moderate" social Democrats to squash the spartacus uprising. Freikorps for those not so familiar with German history were essentially far right militia groups. So things are by far not as black and white as you make it out.