Hiking with Headphones?

So I understand rocking out in the car, sporting the earbuds on a road run or even a bike ride, catching a bit of the playlist while walking around town, but seriously on a hike? Yesterday while out on a trail run, which I love to do for the benefits of nature, I saw a guy (maybe college age) hiking up with earbuds in. To me that comes off as a very oxymoron.