Why are the prisoners so angry with the newly arrived Jewish individuals?

The struggle for survival and how it creates a lack of solidarity amongst individuals who had to endure the Holocaust is a critical element in Wiesel's work.  One of the most powerful aspects of the narrative that unfolds is that the reader is able to see the absolutely horrific condition inside the camps and what it is like to have to struggle to live, to merely exist.  Wiesel exposes this in many ways.  He depicts it in the fighting for a scrap of bread, where people beat one another for an extra piece.  He demonstrates this in the man who is shot for wanting another bowl of soup.  He shows this in how individuals lose sight of solidarity for one another in their overwhelmingly difficult to survive, in a situation where sons forget their mothers and daughters, and children abandon their fathers.  We, as readers, find it awful and possess a natural tendency to criticize the behavior we are witnessing.  Yet, here is where Wiesel possesses a sense of moral and ethical genius.  In speaking out against such behavior, Wiesel demands that we do this in all of our actions, criticizing the behavior that seeks to demean and dehumanize another.  He also does a masterful job of creating a portrait where criticism is virtually impossible because such actions that reflect anti- solidarity are done for one purpose:  Survival.  What Eliezer sees and experiences helps to forge his identity within such a setting where coming of age involves grasping the most dark elements of human consciousness.

This might be why there is anger for newly incarcerated individuals of Jewish persuasion.  Existing people do not see these new entries as fellow victims, but rather as competitors for the mere subsistence of life that exists.  When the newly arrived people enter, greater competition for living is present.  It would be ideal to observe that this forges greater human community and bonds between one another.  Yet, this is where Wiesel demonstrates that the real inhumanity of the Nazis resided in how their demeaning behavior that robbed people of dignity and collective identity was duplicated in the relationships that victims had towards one another.