We have many nanny state things in place these days, but this isn't one of them
That is your opinion. But, reality is that we do live in a nanny state, plenty of laws tell people how to live their lives, just like parents. This is a good thing usually, but mandatory cycle helmets is a grey area in my view.
The real question is how far do we go in protecting people against themselves?
People who argue for helmet laws only look at one aspect, that wearing a helmet decreases risk of head injury by x%.... so seems simplistic.
But, how many people take more risks when they wear a helmet? How do mandatory helmet laws affect cycling participation? Is cycling healthy and reduce obesity rates? Obesity is a big thing, in fact the human lifespan may start shortening for the first time in history due to obesity related diseases.
Anyway, my view is let adults choose, but make them mandatory for kids who are too young to make balanced decisions .
Make them pay in the health system, ineligible for ACC. Cyclists are high risk, I don't want my tax dollars paying for that. Motorcyclists pay at rego, $528.63 in my case, most of that goes to the health sector. Cyclists don't pay road user charges and that's fine, we dont want that, but if they engage in high risk activities they pay for it. Or make seatbelts optional but mandatory for kids. Same with Hi Vis and whatever other measures are statuted for safety reasons. I hear what you are saying but lets make all safety measures optional, every one, except for kids, it's the same rationale as cycle helmets.