As late as 1972, Queensland officials quoted lyrics from the Rolling Stones' Satisfaction as an example of the ''pathetic nihilism'' against which censorship protected the populace. The contrast between the Stones and Justin Bieber, the central figure in Yore's collage, nicely illustrates the evolution of the debate. Back in the day, Mick Jagger spurred a sexual fantasy or two, but Bieber, with 40 million Twitter followers, rules the internet, a realm that makes possible satisfactions of which the censors of 1972 could not have dreamt. The Canadian star's notoriously obsessive fans produce vast archives of Bieberite pornography: images, videos and stories in which Justin does far more than urinate into a sink. ''By day [Bieber is] a teacher adored and loved by all,'' begins a piece of fan-fic accessible after 30 seconds with Google, ''by night nothing but a mystery.'' In this tale, we're told, the teen idol's mysterious evenings feature ''Domination, Submission, Sadism and Masochism, Bondage and Discipline, Murder, Abuse, Alcohol, Deception and Deceit''. The seizure of Yore's work highlights the dilemma that faces the censorship regime more broadly: simply, the array of pornographic content now available renders any particular prosecution utterly arbitrary and therefore unjust.

The law in Victoria prohibits the sale of X-rated movies, rendering, in theory, the core business of the sex retailers and adult cinemas throughout the state entirely illegal. The police rarely enforce these strictures, for the simple reason that Victorians (who are, statistically, enthusiastic aficionados of porn) would be outraged if they did. Besides, when consumers can download in seconds almost any content they desire, prosecuting the local adult shop (an institution that already seems slightly quaint) becomes as pointless as, well, raiding an art gallery over images produced without any children engaging in any kind of sex whatsoever. The crisis of censorship relates to more than technological change. Since the 1980s, the neoliberal turn has introduced market mechanisms into every aspect of our lives, including sexuality, rendering old-fashioned censorship increasingly anomalous. The market makes, after all, no ethical judgments: at the cash register, $100 worth of smut exchanges at the same rate as $100 of biblical tracts. That's why the old Censorship Board now goes by the name of the Classification Board, presenting its assessments not as moral prohibitions but as tools to facilitate the choices of discerning buyers. Obviously, that's slightly disingenuous: in the absence of, say, a religiously derived notion of obscenity, consumers might wonder why official ratings should carry any more sanction than, say, reviews on Amazon, particularly since the overwhelming majority of porn in Australia never passes the censor's desk at all.

Which is not to say that censorship has disappeared. A widespread but inarticulate discontent with a market that knows the price of everything and the value of nothing provides the preconditions for regular and explosive moral panics. Think of the unfortunate Bill Henson: one minute, acclaimed for art that hung in Parliament House; the next, denounced by the PM as a menace to the nation's infants. If such outcries usually centre on children, it's because of the conflicting pressures converging on the modern family. The career of a professional boy-man like Bieber exemplifies the corporate identification of kids as a market segment exploitable like any other, a process that breaks down older ideas of childhood dependence. Yet, as neoliberalism dissolves the social into the individual, traditional family roles become more ideologically important, with the home offering an apparent haven from dog-eat-dog market competition elsewhere. On the one hand, we now idealise kids as innocent neo-Victorian angels; on the other, every music video shows sexed-up tween stars gyrating knowingly to the beat. The unease of that contradiction provides obvious opportunities for demagogues and chancers.

The furore over Yore's collage seems to have been initiated by conservative activists, committed to cutting funding to the Linden Centre for Contemporary Art long before the exhibition about which they claim to be outraged. In a similar fashion, public concern about sexual abuse of children in the NT was unwittingly channelled into draconian censorship laws applied exclusively to indigenous communities, in a direct contradiction of the Little Children are Sacred report's recommendations. In response to raids on galleries, it's tempting to defend the work in question as art rather than porn. That's a mistake - and not simply because Brown's oeuvre (like that of so many modern artists) calls into question the distinction between the two. Too often, critics assert the privileged status of art to imply the incapacity of ordinary people to comment on the work in question, thus feeding the old stereotypes about haughty artistic elitists looking down on the public who fund them. Actually, art should foster widespread debate on important issues - and that's precisely why Yore's exhibition should be defended. To put it another way, we need to talk more, not less, about how sexuality plays out in the world we have created for ourselves. Such conversations matter too much to be shut down by police.

Jeff Sparrow is the editor of Overland and the author of Money Shot: A Journey into Porn and Censorship.