An active society reduces the burden on public health care, take a look at the obesity rates in Australia, especially childhood obesity, shouldn't we also regulate lifestyle choices that contribute to this? How about the explosion of massive 4WDs in Australia? Are you not also subsidising the health care burden those? If you want to keep cyclists safe then build more bike lanes.
It is an excellent defense, because similar logic is often resisted when it comes to regulating lifestyle and food consumption - even though complications from obesity impose a much greater, and growing, financial burden on public healthcare systems.
Are you planning to ban all snowsports? Horse riding? They produce similar or higher levels of injury and disability even with helmets.
>it's not fair for your selfish actions to have a negative effect on everyone else.
If negative externalities are the metric we're evaluating what is and isn't allowed in our society, you're really going to take a pass at cyclist helmets instead of cars? Do you know what the leading cause of child death in Australia is? It's cars
In a society it's not fair for your selfish actions to have a negative effect on everyone else.