Nah it's political stuff alright, you see the early settlers got the Maori to sign a "TREATY" The Treaty of Waitangi to be precise, this stopped the warring between the new settlers and the other tribes who had been battling each other as well.
Maori have this dread fear that their claim to being the first people to settle here will be in dispute if it is found that some other group arrived here first.
A smaller group of earlier natives, the Moriori were driven from the NZ mainland by the arriving Maori and escaped to the Chatham Islands, where the Maori caught up with and ate most of them.
Billions of dollars are given to the Maori every year as "settlement" for the lands they "lost" when the white man turned up, unfortunately this process of paying for land is never ending as this will be the third time the NZ Government has "bought" the land back and paid "compensation" to the many many Maori tribes.
Whole armies of Maori lawyers now make a living out of dragging this process on forever as the hapless taxpayer shells out again and again for supposed grievences.
So you see how important it would be for Maori to hush up and keep concealed anything that did not agree with their version of the past.
Why the NZ government is assisting in this charade is beyond me?