The Freikorps consisted mostly of veterans of the Prussian army, and the specific division that executed Luxemburg and Liebknecht was led by Waldemar Pabst a high ranking official in the Prussian army.
What I am “implying” is that there was good reason why in the interwar period being anti fascist and anti SPD was not an uncommon opinion.
Accepting how the world works is not the same as saying it’s moral.
If someone threatens to shoot you, you saying it’s immoral is not a practical defense, unless there is some kind of higher power like a justice system with a police to enforce it. But the entire point of international politics is that such a force does not exist, just countries with interests.