I recommend the book Solitude by Anthony Storr for a strong counter-argument.

https://www.amazon.com/Solitude-Return-Self-Anthony-Storr/dp...

As a counterpoint to this, see the many excellent articles on The Hermitary.[1]

Also see Anthony Storr's Solitude: A Return to the Self.[2]

Many people have historically chosen solitude for religious or spiritual reasons, to focus on something they wanted to achieve, because they just preferred being alone, or for many other reasons.

Many societies have stigmatized solitude and those who choose it, but on the other hand there have been social movements which have praised and advocated solitude.

[1] - http://www.hermitary.com/articles/

[2] - https://www.amazon.com/Solitude-Return-Self-Anthony-Storr/dp...

There's also Michel de Montaigne's essays from the 1500's On Solitude.[1]

More recently, there are books like The Lonely Crowd from the 1960's, [2] and Anthony Storr's Solitude, from the 1980's[3]

Of course, for thousands of years, spending time in solitude has been greatly valued for religious reasons, for "building character", for coming in touch with oneself, or for creative purposes. On the other hand, modern life, and more recently the media (even before social media) have been criticized for alienating people from themselves and from each other.

[1] - http://www.hermitary.com/solitude/montaigne.html

[2] - https://www.amazon.com/Lonely-Crowd-Changing-Character-Paper...

[3] - https://www.amazon.com/Solitude-Return-Self-Anthony-Storr/dp...

On a similar note, I found this book http://www.amazon.com/Solitude-Return-Self-Anthony-Storr/dp/... to be quite interesting. It discusses about solitude, its necessity and other related issues like depression in detail.