The problem is that these laws are pushed by the insurance and auto lobbies specifically to discourage cycling.
Look behind the big bicycle advocacy organizations in the United States and you'll see serious funding from the American Automobile Association and bicycle companies. I assume the situation in NZ is similar.
I ride helmetless on the road, and I avoid cyclepaths, as I'm far less scared of car drivers pulling something sketchy than I am of rollerblader-dogwalker-strollers pulling something sketchy.
I also live in California, where case law has determined that government is never responsible for injuries that occur off the road and on a bike path.
Additionally, it is flat-out unethical to ride faster than 10mph if you're weaving through pedestrian foot-traffic.
The auto lobby loves cycle infrastructure. It gets cyclists off the road.
