That line comes from a piece in Vox which you may have read already. If not, it's worth the trouble: "The smug style in American liberalism." It's the work of a liberal worried about the fact that liberalism now despises so many of the people it claims to want to help. As the author notes, this is a tendency that's been growing for some time, with the domination of liberalism by feminists and others far more interested in cultural revolution than, say, the economic situation of the working class. That faction pays some degree of lip service to those questions, but what really fires them up are things like abortion and same-sex marriage. The economic complaints seem to be of interest mainly as a club with which to beat conservatives and Republicans.

The rubes noticed that liberal Democrats, distressed by the notion that Indiana would allow bakeries to practice open discrimination against LGBTQ couples, threatened boycotts against the state, mobilizing the considerable economic power that comes with an alliance of New York and Hollywood and Silicon Valley to punish retrograde Gov. Mike Pence, but had no such passion when the same governor of the same state joined 21 others in refusing the Medicaid expansion. No doubt good liberals objected to that move too. But I've yet to see a boycott threat about it.

The piece is fairly long but worth reading in its entirety. There's much in it that I disagree with, beginning of course with a substantial difference in basic political views. But it's good to hear one member of that club telling it what it needs to hear, which is that it's never going to win over people whom it openly despises. 

Finding comfort in the notion that their former allies were disdainful, hapless rubes, smug liberals created a culture animated by that contempt. The result is a self-fulfilling prophecy.

Financial incentive compounded this tendency — there is money, after all, in reassuring the bitter. Over 20 years, an industry arose to cater to the smug style. It began in humor, and culminated for a time in The Daily Show, a program that more than any other thing advanced the idea that liberal orthodoxy was a kind of educated savvy and that its opponents were, before anything else, stupid. The smug liberal found relief in ridiculing them.

I was glad to hear that criticism of The Daily Show. I haven't seen it very often, so it's possible that I got the wrong impression, but pretty much everything I've ever heard anyone say about it has supported that impression, the positives even more than the negatives. As I couldn't help noticing when Jon Stewart left the show, he was regarded as a brilliant political commentator by his fans, which seemed to include most liberals, notwithstanding the fact that he was in principle just a comedian. But it looked to me like his routine was based on taking some conservative point of view, reducing it to a caricature, and smirking at it.