On the contrary, Leninism mandates terror and ethnic minorities are always among the first targets of terror and repression. Stalinism was synonymous with Russian chauvinism, and saw other ethnic groups as inherently counter revolutionary. Chinese communism is also an ideology of Han supremacy. These are all flavors of communism, but Naziism was a particularly German flavor of fascism, so I think the comparison is appropriate. Stalin ran death camps for ethnic minorities, and it was part an parcel with Stalinism.