People rarely listen to background music. The music played in the gym is loud and fast. It is supposed to help people exercise. This may be great for an aerobic class, but what about those using other equipment? The chances of the rhythm of the music coinciding with the rhythm of the treadmill or the elliptical machine are slight. As for strength training, the best technique involves moving slowly. The music in the gym is not slow.
Many people in the gym wear earphones with their own music, but it has to be loud in order to compete with the background music. I don’t yet wear a hearing aid, but I don’t want to damage my declining hearing by loud music. My choice would be to have no music and let people who want music to bring their own. But the young people in the gym, many of them employees, think that the preference for loud music trumps anyone’s preference for silence. It is a good gym, but I may be buying noise canceling earphones.