Fascism can't be stopped by fact-checking

I continue to be struck by this quote from Hannah Arendt in The Origins of Totalitarianism:

 “This method [of infallible prediction] is foolproof only after the movements have seized power. Then all debate about the truth or falsity of a totalitarian dictator’s prediction is as weird as arguing with a potential murderer about whether his future victim is dead or alive – since by killing the person in question the murderer can promptly provide proof of the correctness of his statement. The only valid argument under such conditions is promptly to rescue the person whose death is predicted. Before mass leaders seize the power to fit reality to their lies, their propaganda is marked by its extreme contempt for facts as such, for in their opinion fact depends entirely on the power of man who can fabricate it…In other words, the method of infallible prediction, more than any other totalitarian propaganda device, betrays its ultimate goal of world conquest, since only in a world completely under his control could the totalitarian ruler possibly realize all his lies and make true all his prophecies.”