So Why Don't We Treat Communists Like the Nazis?

From Arts and Letters Daily, a link to an attempt by Slavoj Zizek to explain why Communism should not be condemned in the same way as fascism of the Nazi and Mussolini varieties. I think it fails. Zizek states that the difference between Stalinist Communism and Nazism is that Stalinism was a failed attempt at emancipation while Nazism was a "radical new evil". In my (non-historian) opinion, Nazism is a relative of Stalinism, created by individuals in response to what they saw as the flaws of communism. Both Hitler and Mussolini had ties to the Communists before becoming Fascists, both chose to attempt to implement socialist economic models, and they used the same methods of terror and coercion to intimidate their opponents and cow their own people as the Soviet communists did. The use of terror in Bolshevik Russia started with Lenin and Trotsky, not Stalin. Stalin refined it and added insanity to the mix. The only difference between the Stalinists and the Nazis was the choice of groups to target. Somehow Zizek thinks that makes all the difference. Considering the respective results, it was a distinction without a difference.