This belief is completely incorrect. Helmets increase survivability and decrease the degree of injuries in every respect. This is a very well-studied phenomenon with many public and peer reviewed sources. [1]

To respond to the 'nuance' of your remark, that helmets change rider behavior for the worse, resulting in higher aggregate injuries - that is also incorrect. The passage of helmet laws results in significant reductions (20-50%) in head injuries and deaths. These are reductions among the same population, in the same geography, in a short timeframe. It is indisputable.

If the total number of recorded injuries is going up, it's because ridership has increased. Ridership is up for lots of reasons, population growth and health benefits being two of them. Cycling is a terrific way to improve your overall health, even when the risk of injury or death due to cycling is taken into consideration. [2]

And if manufacturers profit from improving the health and safety of a population? Good.

[1] https://newrossgreenway.org/bicycle-helmet-vs-no-helmet-stat... [2] https://pmc.ncbi.nlm.nih.gov/articles/PMC10546027/

> Helmets increase survivability and decrease the degree of injuries in every respect.

Of course a helmet increases survivability of a head injury in a crash, that’s indisputable. But of course there is a window: some crashes are so minor that they are already survivable without a helmet; and some crashes are so bad that a helmet cannot help. And of course many injuries are not to the head at all.

The first-order effect of cycling helmets is definitely positive! But what are the second-order effects?

> To respond to the 'nuance' of your remark, that helmets change rider behavior for the worse, resulting in higher aggregate injuries - that is also incorrect.

There is evidence that they decrease the number of cyclists; and there is evidence that they change the behaviour of drivers.

When Western Australia imposed cycling helmet laws safety got worse: http://www.cycle-helmets.com/

To be fair to the previous poster, there were some studies (from Australia I believe), which showed an increase in bike accidents with helmet laws. IIRC they didn't have a good explanation, but thought it could be due to more risky behaviour, but also cars being less considerate if people wear helmet.

There were also some studies that showed that for population health bike helmet laws might be a net negative, because it prevents more people riding bikes and the positive health benefits of riding outweigh the slightly increased risk of biking even without a helmet.

>Why Danes Don't Need Bicycle Helmets (2014)

https://www.sierraclub.org/sierra/2014-5-september-october/g...