It helps to be small & pragmatic. People (mostly) follow the rules and politicians (mostly) only implement rules with broad support. Police have wide discretion to apply laws and (mostly) do this to benefit public good.
That's not to say we don't have problems, of course, but this particular law is seen as a compromise approach to public health that more-or-less works for everyone.
Australia/New Zealand have a... very, very, very deep-seated feeling of inadequacy, comparing themselves to large Anglophile nations.
There's a genetic urge to "impress Mother England."
For Australia, also a deep seated desire to prove they're not an island of criminals.
For New Zealand... a deep seated desire not to be left off maps.
It's not so much size... there's just a culture of needing to be a better place to live than America. To stop people moving away.
Edit: root cause. Not benefit.
The idea that there is a genetic urge to impress England is bizarre, typically about 50% of people support becoming a republic. Some recent data in [0]
Australia's original status as a penal colony seems to be held onto as trivia externally but is entirely irrelevant in modern discussion (as it should be as it stopped 150 years ago). Thinking that this is something Australians think about suggests that you have a very outside perspective.
I don't know what a culture of needing to be a better place to live than America means. I don't think being a good place to live is a culture, I think it's an objective of a society.
[0] https://www.smh.com.au/politics/federal/support-for-republic...
Per https://en.wikipedia.org/wiki/1999_Australian_republic_refer...:
"With republican models of one form or another winning a majority in opinion polls prior to the referendum, it was expected that the republican referendum would pass. However, the question put was for a particular model of republic with a head of state appointed by Parliament. This was opposed by some supporters of a republic, who preferred a directly elected head of state. Some of these, such as Phil Cleary, advocated that republic supporters vote "No" in order that a future referendum could be put on the directly elected model. Some commentators—including the president of the Australian Republican Movement, Malcolm Turnbull—identified this split within the republican camp as a key reason for the referendum's failure."
Australia is culturally downstream from America though, so you're right about that.