(National have delivered) tax cuts that put extra dollars in the pockets of only those who don’t need them...This was only a throwaway comment in the general scheme of the post, so what follows is slightly unfair, but hopefully stimulating nonetheless.
What does it mean to need anything? I don't think that the concept of 'need' is strictly meaningful in this sentence, which admittedly is quite common usage. It seems that a concept of 'need' has meaning only in a relational sense - A 'needs' B to do P, which means that without B, A could not perform P.
Often we associate 'need' with what is really just a strong desire - everyone as a child had a toy or similar that they said they 'needed', but in reality just wanted really badly. Occasionally however, and this is the sense I think Curran is getting at, P is equated to 'to live', or even more loosely, 'to live comfortably, or in a manner we might consider a minimum in society'. In these circumstances P is often not stated - we say that people 'need food' rather than 'need food to live', or 'in the modern age, everyone needs access to the internet'. Here we have to become very careful of abusing the word 'need', and I think if we force ourselves to always state what the things are needed for, it can be quite revealing. When we leave out our P's, we allow a whole lot of assumptions to be made.
What does it mean to say that rich people don't 'need' tax cuts? Obviously people need money to live, and the rich don't 'need' any extra help here. I would hope that the amount of people that actually do need extra money (on top of current transfers) to survive in New Zealand is vanishingly small. But I also like to imagine we live in a society slightly less bleak than one where people are only permitted wealth that meets their basic physical needs. The Labour Party is not a communist party, and I am sure they agree with me. But this confused rhetoric is indicative of a party that is not serious about ideas but cheap political partisanship and playing off the visceral disgust many New Zealanders feel for small groups of their compatriots whose supply and demand curves for labour are sloped differently.
Here are a few more meaningful statements Curran could have made:
"National has provided
1) ... tax cuts that will generate lower Keynesian multipliers as the rich have a lower MPC"
2) ... tax cuts that will mainly focus on the groups that gain the least marginal utility from them"
3) ... tax cuts that make our tax scheme less progressive"
etc. Obviously it is silly to expect a politician to talk like an economist, but even something that gave the gist of the above would have been far more meaningful, and easier to judge a) its truth value and b) value as a goal.