> Helmets protected me in bike racing where they're already mandatory.
> They do not protect most riders at all.
This is a textbook example of non sequitur.
I would also add that it's so obvious that it hurts, because, simply, most bikers have never raced and never will, so to them what is cruise speed for a professional biker is where the risks are.
I too have been a professional car driver in (very) minor leagues, that doesn't mean that what protected me while racing cannot protect my dad that never like driving and has always been very bad at it.
Helmets protected me in bike racing where they're already mandatory.
They do not protect most riders at all.