What is the explained main problem/ dilemma in The Boy in the Striped Pajamas?

I think that one of the main issues that is explored in
the novel is how human beings act and should act in the face of unspeakable horror. 
Essentially, the novel asks the question of what individuals do when there is
suffering.  Bruno becomes our guide through this maze of ethical action.  When Bruno
becomes aware of something that is not right or not in synchronicity with his moral
sense of order, he acts or develops a sensitivity towards those who are victimized by a
setting that lacks his own understanding.  The only instance where this wasn't evident
was when Bruno was silent as Shmuel was demeaned.  He ended up apologizing for this and
made amends for this silence.  The novel explores the dimensions of human action in the
face of social pressure and the result of this exploration is a resounding affirmation
of how human beings must seek to transcend their setting when contingencies do not act
in accordance to universal values such as care, compassion, and understanding for the
plight of another's suffering.  It is in this where the novel seeks to focus its
attention on the problem of human suffering and individuals' reaction to
it.