I wear headphones and listen to music all the time when biking. There is absolutely no problem doing so. I watch where I am going and I can easily hear any meaningful sounds through the music.
Or do you mean headphones that completely shut off the environment? That would be pure stupidity and neglect. But also something far different from just listening to music on a bike.
I ride to work every day. Most of my commute is on a popular bike path. I always warn people before I pass them. Every few months, someone decides to do a U-turn or a left turn, without looking, right into my path, while I'm passing them, leading to a near-collision. So far, 100% of the adults who've done this have been wearing headphones. (I've had one kid without headphones do it; I said "on your left" and she got confused and veered left into me. Now I just say "passing.")
Based on this, I think joggers and cyclists with headphones are significantly more dangerous to themselves and others than those without.
Of course, it's possible that you are different and can hear fine through your headphones, but I'm skeptical. (Just as I'm skeptical of people who claim they can drive fine while talking on the phone, or while drunk.)
Correlation is not causation. I would much rather think that those people were distracted or something. Not giving attention to their environments.
I CAN hear fine with my volume setting. Believe me.
Listening so loud or with headphones that cut out other sounds is dangerous, of course. I was not talking about that and I thought I had made that clear.
Just don't tell me that I cannot listen to music while biking. Unless you want to argue about the possible distracting itself, then we could go on about car radios.
The problem is that the headphones are extremely close to your ear drum. Depending on the volume, you are more or less tuning out the environment completely when playing any kind of music through headphones.
Sometimes people will yell at you when they see a possible accident happening but you wouldn't be paying attention through your music. You need to hear cars accelerating quickly in case you need to get out of the way or avoid them.
There is no greater fallacy than wearing both headphones on your ears while biking. What is more important you, music or your life?
Try going without headphones for a month or two, then put them back in. You might be surprised at how much useful info they block out. I say that not as a command but a suggestion based on my experience. It took me a while to get used to hearing and analyzing what's happening around me. And that was mostly in a car, which is already a pretty loud environment.
The problem is that most people use their headphones with absurdly loud volume. I know this because when you pass them you can hear their music, which means they are probably damaging their hearing. I always keep the volume as low as possible, such that it's not louder than the traffic around.
Or do you mean headphones that completely shut off the environment? That would be pure stupidity and neglect. But also something far different from just listening to music on a bike.