rights gained in the 20s in both countries were lost in the 30s.
even just in the 30s, the 1934 aboriginals act was a step forward, the '36 western australian act and the '37 assimilation policies steps back. In NZ, you had a royal commission into treaty breaches giving land back in the '20s that gets confiscated again in the '30s and all the injustices Ratana was rallying against. Immigration both nations were continually narrowing restrictions on who could come in so they could protect white british identity, they went about it in different ways and each had different target groups but it's history and its not nuanced to say that because it sounds bad it must be black and white bad so cant be true.
no one is denying nuance, unless say simplifying what the other said for the sake of having an argument instead of a discussion.
There was alot of nuance, but not enough to say times were good and things were all fine.
Racism was a major driving force in politics, thats not a criticism or 'being harsh' its just a fact. As it wasn't seen as a negative at the time they were quite bold and open about it. theres no need to deny it for sake of feeling good about it now, there are the decades of great strides since, before and during too to celebrate without having to deny the steps back and pretend they were never there.
Even the debate about abolishing the white australia policy was about economics with both sides being vocal with views that even the far right would be ashamed to be caught saying today. It was very important at the time, bipartisan and there's no getting round it. You can say oh compared to one the other the worse but both were still very racist. It was as they say 'a very different time' and what with nuance they put the lines of good and bad in different places.
more nuance is the thing, going backwards happens in history about as often as 'forwards' because as you say, nuanced. and its not an attack to say the policies and governments of the time were racist, its just true. It's no more an insult or harsh than to point out they didnt have colour tvs no need to get in hackles to defend them, they didn't think it was a bad thing and wouldnt want you to.