Not many people know the history of the treaty. It basically was signed under duress. Prior to the meeting where it was signed all but one of the Maori tribal leaders were against signing the treaty, even the Maori version. What was said at the signing was purposely never recorded, but considering the existential threat of the New Zealand Company (NZC) on the horizon (the primary reason a treaty was even being discussed), it is believed that the Maori leaders were basically given the choice of 'sign this treaty and be a part of the British empire, or don't and have no legal rights against the whims of the New Zealand Company'.

The New Zealand Company was a private British company with the goal of obtaining as much land as possible at any cost, and the Maori would have had zero legal protections unless they were part of the British empire. Without a treaty the NZC would have been able to push out the Maori entirely with no repercussions. The British people who brought the treaty to the Maori leaders knew this was coming, and wanted to avoid it.

Signing the treaty was a quick and dirty solution to the quickly approaching NZC and was responsible for preventing the worst of the damage, but it is a very flawed document. The translations were rushed, and vague. Basically everyone was against signing it, but they knew it was the least worst option available. It was never designed to be the core document underpinning a nation, merely a speed bump to stall the private annexation of New Zealand.