Which seems to me to be to humanize the families of kids who commit terrible crimes. There is not much difference between the cop's kid and Jamie. The cop basically admits he's a crappy Dad. There is a lot of randomness involved in life. "There, but for the grace of God, goes I". I thought they played on the hopes that probably arise in these families, "Oh, he was bullied, maybe that will make the crime less serious." In the end, those hopes are disappointed.
I thought the acting was fantastic. The kid who played Jamie was amazing. You may remember his dad from Snatch, where he played Turkish's sidekick.