Time and time again, the people of Sighet doubt the advance of German Army. Why?

Part of the answer to this question lies in human nature.  I don't say this to disparage or dismiss anything, but rather evoke a painful element about the Holocaust.  One of the philosophical tenets behind the Holocaust was the idea of denial and rationalization about the atrocities being committed by the Nazis.  There was a great deal of indifference and dismissiveness about the reality of the situation.  Part of this was motivated by a sincere desire to not accept the truth, so horrific and brutal that to do so was inconceivable.  The people of Sighet engage in this level of denial.  At the same time, Wiesel is very quick to suggest that some of the true terror of the Holocaust was the idea that the reprehensible behavior practiced by the Nazis was actually replicated by some their victims to one another.  This cycle of abuse could be seen as practiced by individuals of Sighet, as they dismiss and discard the prophetic warnings and visions of Moshe the Beadle.  Wiesel is quite compelling in this regard when he suggests that indifference is perilous because it empowers the aggressors.