The brutality is presented as nothing more than an extension of the boys nature. Summa Human nature is both passively and actively selfish. We tend to care more about our own comfort than the pain of others, so comfort is what we will seek. That sounds bleak but there is an antidote. There are three things that serve as a necessary corrective of selfish behavior.
Law can provide an anchor to restrain blatant aggressive selfishness.
Those two men went to jail for their crimes. They can t do the same thing in prison and they are less likely to do that same sort of thing when they get out. The old saying, all charity begins at home is only the beginning. The family is the basic building block of our society for the simple reason that it teaches us to need one another. While the above two institutions are both good and needed, they fall miserably short without this final tincture.