We were once warriors

The Maori value strength. As a man, strength is still the most honorable title one can receive; Whether the Maori are embracing their traditional roots or are living lost in the suburbs or underpasses the traits of a warrior are the greatest thing one can be. Physical ability is shown by many of the characters. Boogie transitions between both worlds. He first displays his power by stealing car radios, and in the end by emersing himself in his roots, and performing as part of the group warrior dance at Grace's funeral. Jake, along with most of Maori he hangs out with, is incredibly muscular and enjoys large amounts of drinking, punching, and to a lesser degree, stabbing.
The violence seems to originate from a frustrating confusion of what their life is supposed to be about. Each character is striving for purpose. In their own way, many of the children try to discover their culture. Boogie's older brother Ng, gets his face tattooed and jumped into a Maori gang. Boogie practices throughout the night a ritual warrior dance, and Grace reads and tells Maori stories. Natural and meaningful connections to the Maori past are viewed as the only salvation. The movie most sympathetically looks at Boogie's on going enlightenment. At the dinner table he says to his older brother that he likes his face tattoo. His brother asks if he wants one. He declines, saying that he wears his on the inside. In the movie the need for internal development is linked with, also, an abandoning of modern society. Boogie represents the model for how Maori can transition back to what they had been.
Although never out right defeated, the Maori moved out of the hills, their ancestral homes for thousands of years, and into a world that didn't have a need for them. The oppression of the Maori is invisible. The Maori live in dilapidated houses and are viewed as menaces by the local police department. There isn't an economy to support them. The oppression is a result of the policies of the 85% pakeha (basically white people) of the population. The whites are nowhere to be seen in terms of friendship. When white people are present, it is only to take a child away, and arrest or convict somebody. Jake Heke, the charismatic psychopath, loses his job, but doesn't worry, and waits for the welfare check. Being unemployed pays about as much as having a job. By embracing modernity, or at least, by existing in industrialized society, they have become refugees in their own country. They don't, or aren't allowed by the power structure, to participate in any meaningful way in the economic or political system, so they are stuck.
The worst elements of world are unleashed upon Grace. She is nurturing, and when Jake punches his wife, and is in charge of running the family. She takes on many of the injustices that happen to Maori (and also Maori women) in every day life. These injustices destroy her. Though she represents the cruelties that are subject to the Maori, and sometimes the evils that Maori do to other Maori, she is also a thread connecting past and present. She is buried in the hills her mother grew up in. Her death helps connect the family to their origins and also shows how a broken society can make the innocent victims. The rape committed against her could, I suppose, could just as easily happened in a traditional Maori society, but it doesn’t seem as likely that she would hang herself. The developed world left her with few outlets to find help.
The countryside is, like so many movies we have seen, shown in a positive light. The picnic scene is, unlike most of the movie, quiet (except when Jake talks) and beautiful. The funeral is held in the near mountain like regions of New Zealand. It is the most scenic place in the movie. The city is cold and violent. Mostly it is just ugly. The city is a place to get drunk and waste away. In the country, in the past, they were warriors, and the movie seems to say that to develop as humans that is where they will have to return.