I was responding to ru4por, who I'm sure didn't intend to insult handicapped people. And I admit, I shouldn't generalize about headphone wearers; some manage it just fine. It's the portion of them that are disengaged, so caught up in whatever they're listening to that we have to constantly get their attention for routine things like scores, who are annoying.
On the one hand, it always strikes me as anti-social. "I'm playing with you, but keeping myself apart," is what the headphone wearer seems to be saying. On the other hand, I dislike people playing music aloud, so I'm thankful that they're keeping it to themselves.
And of course, we try to be tolerant of the range of preferences people bring to disc golf, unless we wish to play alone. And even more so in leagues, since people bring to them varying degrees of seriousness, on the scale between tournament play and very casual play. Those variances include distraction and consumption and rules compliance; we just have to work it out amongst ourselves, if we can, and the more civilly we try, the more likely that we will.