Why do Eliezer and the other prisoners respond so emotionally to the hanging of the child? Were the SS "more preoccupied, more disturbed" than usual?

The child is hanged for allegedly being part of the Resistance. This child is one who people really love. Besides the fact that it is a beloved child being hung, the child dies a very slow death. When he is hung, his neck does not break because he is not heavy enough to cause the force of the fall to sever his spinal column. If this had happened, death would have come quickly. Since his spinal column is in tact, he must die from asphyxiation. This makes his death slow and painful and the men who are forced to watch begin to cry. Someone asks "Where is God"? A voice from inside Eliezer tells him "God is on the gallows".