The answer is very simple: from the 1920's until the fall of the Soviet Union, "left wing" meant supportive of the goals of the Comintern, "right wing" meant opposed to the goals of the Comintern. Thus, Tories, Republicans, Nazis, monarchists, fascists, Democrat Cold Warriors, Christian Democrats, classical liberals, nationalists of just about any description, were (and by linguistic inertia still are) called "right wing", while Labourites, Democrat pacifists, Communists, socialists, social democrats (esp. of the "nuclear freeze" supporting type), etc. were and are called "left wing".