That was pretty much the discussion my wife and I had, speakers playing music for everybody else in traffic just makes you annoying.
A few little speakers on your motorcycle pumping out tunes might be bothersome to other people? I suppose if you have it cranked to 11, sure, but I have a big 4 speaker stereo in my fairing and although I turn it up at speed, when I slow down...I turn it down. Simple solution, and if my choice of music (Classic rock on Sirius most of the time) is bothersome to someone else sitting directly next to me (which is about as close at they'd have to be to hear it once I turn the volume down), well, too bad for them, they're looking for something to be upset about at that point basically.