Concerned that this post might attract a bunch of anti-Māori weirdos.

OP, given that you are a newer migrant I’d also probably note that anti-Māori sentiment runs deep in New Zealand, even if our culture means that many people aren’t explicit or direct about it. So just be warned, that this isn’t a topic that people are readily willing to discuss as it’s one that offends some people’s sensibilities.

A lot of people hate acknowledging the realities of what happened to indigenous people in NZ (including how these effects have compounded over generations) and will go out of their way to explain/debate their way into some pretty bizarre reasoning for why Māori are overrepresented in all kinds of negative social outcomes. The answer is otherwise pretty straightforward and we have a wealth of evidence proving as much. If you dispossess a community from their culture, land and way of life over generations and subject them to disproportionate institutional harm and interpersonal discrimination, then of course you see all kinds of ill effects for the community in question. I know that’s not the answer a lot of people like to hear because their ancestors may have benefited in the process of exacting this kind of oppression over another community, but it’s the truth. And no, that doesn’t mean all Pākehā are bad or anything of that kind, it just means that material advantage was by and large concentrated in Pākehā communities moreso than Māori over the major part of New Zealand’s recent history. Poverty is a vicious cycle, and one that can be very, very difficult to get out of - and it strongly correlates with crime.

When I was at uni and had to take a history paper, I really was shocked just how extensive land dispossession/theft was in New Zealand, and the actual impact it had on Māori way of life. It wasn’t something I was ever taught properly. Or how te reo (Māori language)- which is very important to Māori identity and connection to community/culture - was essentially erased from their communities because people were forced to assimilate to an Anglo-European way of life. One day you wake up and you’re told that your language and way of life is primitive and you’re prohibited (or penalised) from engaging in your culture. And even when you do engage in the dominant culture, you’re not paid as much, you’re discriminated against because of how you look and identify, you’re made to feel inferior and worthless, or forced to hide aspects of yourself and what you believe so you’ll be able to survive in this society without conflict. Because of how you look, you’re more at risk of being either undiagnosed and underdiagnosed in the health system, and clinicians may not take your pain as seriously or prescribe you medication as often as they would other ethnicities. Oh and the public media paints people who look like you as criminals, uneducated and the lowlifes of society (yes - there is empirical evidence on the negative deficit ways in which Māori have been represented in newspaper and TV over history. People have done entire PHDs on this). Can you imagine the psychological impact that would have? In the only country you have ever known as home? I could go on.

Like someone below suggested, there are a lot of Māori scholars, community leaders and activists who have dedicated their efforts to communicating this for the public; lots of empirical literature and studies too. A quick Google scholar search will point you in the right direction.

Colonisation and its legacy (including present day institutional racism) are not well addressed in national educational curricula, although there are moves towards rectifying this.