+1 for what Chipcom said. If you want to wear a helmet - cool, your choice. If you want your kids to wear one - that is fine too. If you think the whole world should wear one - fine too - you have the right to have your opinion.
Just understand that if you include the whole world, you are a MINORITY - and realize that the USA is where people don't depend on bikes normally for transportation.
Perhaps the real thing is that most people in the USA are lousy cyclist?