Some of them have been mistreated at home, perhaps even to the point where it could be called child abuse. Moose works as a saw boss at the camp. I figured it was Moose and Lefevre coming home drunk from Camp Three.
He is unsympathetic and always picks on others, so nobody likes him. Moose, after all, has shown himself to not be the brightest bulb.
When any of us sees bullying, we should not keep silence. There are all sorts of examples of deaths by hazing in the military, the fraternities, and even some sports teams.
How will Sparrow relate to others in the future? Moose has an unnatural need to take his jealousy out on Cecil, for example by giving him jobs much too hard for anyone.
Moose is picking on him because of this, and because of his physical appearance, which is less strong than his own.
He has set his mind on studying art; he makes beautiful things out of plain wire.