the totalitarian terror regimes of the twentieth century.

That's the phrase you use to avoid provoking the irrationality that comes from referencing Hitler?

France's was a case of willingness to convict nine innocents lest a guilty person go free, while a significant part of Germany's was gratuitous - this is a qualitative difference.

While "X was the worst thing until Y" can inappropriately associate X and Y, there are in this case many connections and similarities between X and Y.