I was a member of the Cascade bicycle club back when I lived in the Seattle area. I got into it with the president of the club about this law. I was as against it as I am against seat belt laws. By all means people should wear seat belts and should wear bicycle helmets, but making them arbitrary laws is just insulting to people who claim to be in a free nation. For the record, I feel the same way about motorcycle helmet laws. Interestingly, I now live in a state where we are not required to wear helmets, yet most people on the freeway do.
These are ridiculous laws. It should be a matter of personal choice.
As is, these laws have become purely tools for revenue generation and an easy way for police to start a fishing expedition.
Same in Texas. You can ride a motorcycle without a helmet, and yet seat belts are required to drive a car. So when they claim it's about "your safety" it's complete bullshit. It's about money. Period.