Why did right wing groups call Weimar leaders November criminals?

Correct answer: Because they were blamed for Germany's defeat and the Treaty of Versailles

Right-wing nationalists spread the false claim that the Weimar leaders who accepted the November 1918 armistice and later the Treaty of Versailles were responsible for Germany’s defeat. They therefore branded them “November criminals” as political propaganda. They were not members of the Kaiser’s army. Exam tip: link this term with Germany’s defeat in the First World War and the Treaty of Versailles.