Why did Māori start killing their children at alarming rates in the 1990s?

Between 1978 and 1987, Māori and non‑Māori children were dying at almost the same rate - around 1 child per 100,000 was murdered. Then suddenly, something snapped. By the 1990s, the Māori child-homicide rate more than doubled, while the non‑Māori rate actually dropped. So what the hell happened?

Between 1978 and 1987, child homicide rates in New Zealand …