It’s a personal preference thing, without a doubt.
I’m a bit of a philistine in that I often listen to music whilst walking, and feel it enhances the experience (as well as drowning out my puffing-and-panting). I’ve even got an “uplifting” playlist. I can fully see why some think it’s against the point of getting out in the hills.
To be philosophical, I think that nature generally trumps man ie I prefer the beauty of a natural scene to even the best man-made design/architecture (hence why I love walking), but I think music is one area where man trumps nature. Although a peaceful, natural background noise is very relaxing, music can move you, and on the hills, it can be the best of both worlds.