I will listen, sometimes, when I play alone. I will use a speaker, or put my phone in the little storage compartment of a Sun Mountain cart. I play the volume low, and if I get close to anyone, I turn it off. I have never played music when playing with anyone else, and never played in a group when music was being played. I walk, but if someone in a cart played music at a low volume, I don't think it would bother me.
My personal opinion and experience indicates to me that there are a whole lot of people who are simply unable to handle quietness. They get up in the morning and the first thing they do is turn on the TV. If they're in the car they turn gotta have music or talk radio. If they could find a way to have a television on their push carts they would. It's not the music, for them - it's the noise.