These people probably think Stalin was a conservative.
Actually, many of them do. Or at least "right-wing"... I kid you not. Political repression is an organic output of any liberal/leftist gov. Unless countered by conservative forces, all leftist govs eventually turn totalitarian.
Stalin was not a conservative, right-winger. He was a garden-variety leftist who liked killing and repression just a little more than the average leftist.