I'm all for personal choice and not treating grown adults like children, but if helmets were unsafe why do all the Moto GP racers wear them? Why do Forumla 1 drivers in CARS wear them?
That's a specious argument at best.
I think the main difference is one scenario involves racing where the risk is much, much higher. Your point is well taken however and I am anti helmet law.
most racers in helmets also have neck protection as well. that neck protection is not feasible on the road, as it limits how far you can turn your head.
when racing you don't need to turn your head, you have spotters over the radio.
the usual argument for "unsafe" is vision impairment.
IIRC there has been some research that shows certain types of injuries were increased with helmet use, like collarbone injuries/breaks.
IMO the pros outweigh the cons. I have crashed twice without a helmet, with no dain bramage. I have also crashed with a helmet, and hit the ground with my head.
It is possible that without the helmet my head would not have hit the ground, yet because I had the helmet on my head stayed in one piece.
It's a vicious cycle.