I suppose if I had to try and find his points they would be:
* "headphones are bad because they cause us to be isolated"
* "Millennials are seeing themselves as hard done by"
The second point might not be what the author means though, but the former has strong tones throughout the piece.
I do not agree, headphones are a way of having some level of privacy in an increasingly crowded and public world. We are expected to use public transport, for the good of our wallets and the good of the planet. However those public transport machines are especially loud (Bus engines are incredible) and we're beholden to the whim of shitty teenagers playing rap music at 100db from tiny speakers.
This is before I mention the increasingly popular open-office work environments, which put a large number of people in a room together for 8-10 hours every day.
I do not want to hear Debbie finalising that sales call and then talking shit to her colleague about the guy from third.. I want to get my work done and focus. Headphones are the only way to do that in a modern work environment.