I sort of straddle the line on this one.
On one hand, I agree with the points that some of you made about feeling recharged running alone and being with nature. I think some of my best emotional recharging occurs when I am training hard, focusing on running, and occasionally letting my mind wander. I think music can screw up your cadence a bit and it may make hard training tougher. I hate runners who are clueless to their surroundings too, so it can be annoying for other runners.
On the other hand, there are some days where you are down in the dumps, or its especially nice outside, or the mood strikes, and you would prefer to listen to music on an easy day. I love throwing my phone in an armband, putting on my headphones, and cruising for a 1.5-2 hour long run while getting lost in a DJ mix (shoutout to Above & Beyond and Eric Prydz's essential mixes). I live in Chicago, and a few of these long runs on the lakeshore path each summer are amazing.
So, big picture, I get why some runners look down on headphone users if they think those runners are using the headphones as a crutch, or are clueless using them, or missing out. But those judgmental runners also need to understand that occasionally they're missing out too.