You are missing something. He is positing that it is current strain of "liberalism" itself that works in conjunction with social media usage that creates the problem. The article is very clear about this, including citing research to this effect, although he ultimately disagrees with the conclusions that the researchers reach. But the data itself is instructive. In a nutshell, the belief in the attainability of a utopian society is the problem. That's a poor representation of the totality of his argument, so I urge you to re-read the piece and see if you can pick up on this thread. Also, The Coddling of the American Mind is an indispensable book length exploration of this phenomenon, if you want a lengthier and ultimately more fully argued explanation. Cheers.