I spend most of my time, professionally speaking, writing about movies and books, and during quiet moments, I like to entertain myself by imagining what might happen if the equivalent of poptimism were to transform those other disciplines. A significant subset of book reviewers would turn up their noses at every mention of Jhumpa Lahiri and James Salter as representatives of snobbish, boring novels for the elite and argue that to be a worthy critic, engaged with mass culture, you would have to direct the bulk of your critical attention to the likes of Dan Brown and Stephenie Meyer. Movie critics would be enjoined from devoting too much of their time to “12 Years a Slave” (box-office take: $56 million) or “The Great Beauty” ($2.7 million), lest they fail to adequately analyze the majesty that is “Thor: The Dark World” ($206.2 million). What if New York food critics insisted on banging on about the virtues of Wendy’s Spicy Chipotle Jr. Cheeseburger? No matter the field, a critic’s job is to argue and plead for the underappreciated, not just to cheer on the winners.

The issue is not attention — any critic who ignored mass taste entirely would be doing his or her readers a disservice — so much as it is proportion. Music critics are as snobbish as any other variety of critic, but lately, their snobbishness has been devoted to demonstrating just how unsnobbish they are. Given Katy Perry’s string of No. 1 hits, a well-honed argument about her appeal is a welcome addition to the musical conversation. But should gainfully employed adults whose job is to listen to music thoughtfully really agree so regularly with the taste of 13-year-olds?

Poptimism has become a cudgel with which to selectively club music that aims for something other than the whoosh of an indelibly catchy riff. Its Kryptonite is indie rock, subjected to repeated assaults for its self-seriousnessand rockist fervor. Bands? With guitars? And sometimes with beards? Don’t ever tell a poptimist critic that you love the Strokes’ later albums or think the National are geniuses (guilty on both counts). “Rock music,” Slate’s Carl Wilson sniffed when reviewing the National’s most-recent album, “has died and gone to graduate school.”

So why is music criticism more or less alone in this affectation? Unlike those other disciplines, it has had to wrestle with the fact that music is now effectively free. Music criticism’s former priority — telling consumers what to purchase — has been rendered null and void for most fans. In its stead, I believe, many critics have become cheerleaders for pop stars.

It is no accident that poptimism is an Internet-era permutation. Obsessive coverage of stars like Drake and Justin Bieber drives Web traffic in a way that more judicious, varied coverage of the likes of, say, the Tuareg guitar wizard Bombino generally cannot. Once, we learned about new music by listening to the radio, reading Spin or watching MTV. Today MTV is largely a reality-TV channel, and most people prefer their iPods or Spotify playlists or Pandora stations to fusty radio programming.

In this way, poptimism embraces the familiar as a means of keeping music criticism relevant. Click culture creates a closed system in which popular acts get more coverage, thus becoming more popular, thus getting more coverage. But criticism is supposed to challenge readers on occasion, not only provide seals of approval.