I don't wear a helmet when I ride my bike. Am I crazy? Probably not, but surely many people think I'm being stupid not to wear one. It can't hurt, they say. And it might save my skull.
True enough. But I don't see what makes bicycle riding more dangerous than, say, walking, and we don't think it crazy to go for a walk without wearing a helmet, even though it couldn't hurt. If the danger in biking is that one might fall off, then there is little danger if you are a competent bike rider. If the danger lies in the chances of being hit by a car, then biking is no more dangerous than any other mode of transportation, including walking.
But if we're going to actually get serious about risk assessment and being safe, instead of just exhorting people to wear helmets, then we should discuss every activity and determine what level of risk to one's health is too much to accept. Is skiing too risky? Driving? Flying? Walking? Rock-climbing? Walking at night? You get my point. People die in car accidents all the time, yet we don't think it crazy to ride in one. I think people are nuts to go skiing, yet if they have fun doing it, so much the better for them. I realize that it all depends on how competent one is about these things. There is nothing inherently dangerous about such activities. They only become dangerous when someone really doesn't know what they are doing.
I think people should take the same attitude toward biking. Of course you could fall off and die - but you can also die in a car accident. But many people never get into a car accident because they are defensive drivers, just as many bikers have been riding for years without falling off, and many of these bikers have never worn a helmet.
Chill out people. There are more important things to worry about than helmets.