If I’m two or three bike lengths away and I hear someone’s music, then fine. If I’m ten bike lengths away and I clearly hear the music, then why is this happening? Why would someone feel they need to broadcast their music to others? Sure, some people would enjoy other people’s music. But to others it’s an irritation. So why do it? Quietly playing your own localized music seems more considerate and reasonable.
That being said, I don’t believe any survey results or the potential of irritating some people with their music will influence the behavior of the riders with the loud music systems. And to a point, this is also reasonable. Most of the time it’s relatively easy to get out of hearing range by riding ahead or dropping back.