I'm sure they can indeed imagine the misery the kid is going through.  And I'm sure the thrill hormones run through their blood and that's why they do it.  They don't give a damn about the suffering they're inflicting.  He's of a different social "class" (the word "class" not to be confused with the socio-economic reference).  They just take for granted that they're immune from the same kind of suffering and would certainly never deserve it.  I hope that bully's encounter with law enforcement is a "shock and awe" experience.