How can I analyze Across a Hundred Mountains from a moral perspective?

The author of Across a Hundred Mountains takes a moral stand against the cruelties of immigration. When Juana is on the bus heading to the Mexican-U.S. border, she notices a young boy sitting on his mother's lap and observes, "He kept looking out the window, with longing and resignation. He was not much older than five, but his eyes looked old" (143). The boy sitting on his mother's lap calls to mind the pieta, or a form of sculpture in which Mary is holding Jesus's dead body after he was taken down from the cross. It's clear that the people on the bus are regarded as sacrificial victims. 
Later in the same passage, a girl asks her father why they can't take a bus across the border, and her father tells her, "Because we don't have papers, Carmen. And even though it's just land, it represents a wall. We must go like thieves." The people on the bus in no way resemble thieves; they are hard-working people with their children. However, because the border has been constructed in the manner of a wall, they are regarded as criminals. 
The author's constant use of rosaries symbolizes the saintly quality of the Mexican people who are caught up in a cycle of poverty and forced immigration. For example, at the beginning of the novel, Juana prays with her mother in the following passage: 

Juana watched the flame of the candle flickering on La Virgen de Guadalupe's brown face and dedicated all her prayers to her. Then she picked up her rosary and kissed the metal cross hanging from it. (6)

Juana prays to a brown virgin who looks like her mother, who is, the author suggests, a victim. Despite Juana's prayers, the river continues to rise. As the author writes, "Sometimes it swelled so much the water would overflow, creeping into the shacks like un ladron, a thief."
By using the word "thief" in this passage and in the later passage in which the hardworking Mexican father tells his daughter that they are considered thieves, the author suggests that it is really the poverty and misery to which the Mexican people are subjected that is the true thief, robbing them of their lives and happiness. They are not thieves but are subjected to a life of great cruelty and unfairness.