You don't get it, sure your not listening to music and everything else is blocked out; just like using a cell phone in car, your not blocking out everything. I hear so many cell phone users say the same thing' "use some self awareness and you'll be fine", but they still die or kill someone else. But you are right, you are blocking out some of the noise and/or your attention is somewhere else, and during that time that your zoning you losing valuable time you could have used to avoid an accident. One second lost is a lot of time to die or not to die in.

By the way, I too am a huge music fan, but when I ride my bike I want all my senses at 100%, when I listen to music at home I close my eyes and sit back and crank it up and could care less if a car is speeding down my road.