Not precisely. In non-Communist countries, Stalin worked with "useful idiots" including Social Democrats or whoever could be dragooned to support the Comintern party line at any given point, including Nazis.
Within the Soviet Union all non-Stalinists were ruthlessly supressed, along with Trotskyites and other "deviationists". The varieties of socialism were tolerated where necessary outside the Soviet Union. Within, there was just the one.
What you don't seem to realize is that otherwise normal people fell in love with Josef Stalin. It was a truly pathological abusive relationship.