That's what the other Socialists and fellow-pinko's said about them, to distance themselves.
Labels don't mean much, but programmes do. The Nazis were a Left party, and socialists. There is no such thing as a "right-wing socialist". If challenged to identify a "right-wing socialist", I doubt that any academic on the face of the earth could identify one, with the possible solitary exception of the Nazi Party of Germany, and that is only because the Leftists have always insisted, "we aren't with Ugly over there.....he isn't one of us!" But of course that was an expedient lie.
As between Left and Right, self-identifying and programming as a Socialist has always been definitive: if it's Socialist, it's Leftist.