It used to be so easy to shock the bourgeoisie. You could do it with paint, like Picasso; with words, like D. H. Lawrence; with (dubious) scientific data, like Dr. Alfred Kinsey; or with stand-up comedy, like Lenny Bruce. All you had to do was produce something explicit enough to roil their prudish sensibilities and wait for the outrage to come rolling in.

But that was before the bourgeoisie went bohemian and embraced transgressiveness instead of shunning it. And it was before the old middlebrow culture fragmented, as first cable TV and then the Internet hived consumers off into like-minded communities. In this brave new world, at once jaded and self-segregated, it has become harder and harder to reach the people you want to shock, and harder and harder to conjure up something sufficiently outrageous to appall them once you do. The innocent can wall themselves off from the blasphemous and gross, and the worldly couldn’t care less.

It’s been left to Sacha Baron Cohen, the long-faced, loose-limbed, Anglo-Jewish comedian, to find a solution to this problem. Or perhaps he was forced into it when his earliest comic persona, the dimwitted, wannabe-streetwise interviewer Ali G, ran out of potential targets. Ali G had trapped so many public figures — from James Baker to Naomi Wolf to Donald Trump — in hilarious, idiotic, squirm-inducing interviews that every English-speaking PR representative was wise to the con. All that was left, as targets for Baron Cohen’s ambushes, were people too ordinary to know what they were in for.

The result, in 2006’s Borat and this summer’s Brüno, has been a 21st-century reinvention of the old transgressive game. Instead of dunking crucifixes in urine in the hopes that someone, somewhere, will be mortally offended, Cohen takes a more direct approach. Through his alter egos, an unfrozen-caveman Kazakh journalist and a flaming Austrian fashionista, he sets out to horrify the Western world’s dwindling population of squares, puritans, and reactionaries by invading their businesses, their churches, their campgrounds, and their homes, movie camera in tow.

It’s a win-win scenario, it turns out: First you shock and outrage Middle America with wildly inappropriate antics, and then you turn their shock into a high-grossing entertainment for a more elite and with-it audience.

Better still, Cohen nails his poor marks coming and going. For instance, if the people being imposed upon were openly outraged by Borat, the mustachioed, boorish Central Asian journalist — well, then they were the butt of Baron Cohen’s joke. But if they tried to be kind to a bizarro foreigner, and reacted politely to his casual misogyny, racism, and anti-Semitism — then they were the butt of the joke, and bigots to boot.

Brüno is a variation on the same dynamic. Fired from his hit Austrian TV show, Funkyzeit, after a disastrous wardrobe malfunction, the title character tours the world in search of easy marks — redneck hunters, Orthodox Jews, D-list celebrities, showbiz parents, congressman Ron Paul — who are either induced to say horrifying things by the flamboyant Austrian’s prodding questions, or induced into horrified reactions by his outrageous gay come-ons. (To a hunter, appalled to find the nude Brüno at his tent flap: “A bear ate all my clothes except for these condoms.”) Play along, and you’re a fool; lash out, and you’re a homophobe.

There’s a great deal to say about the moral callousness involved in this approach to comedy, but remarkably enough, most of it has already been said: There’s been quite the Baron Cohen backlash lately, much of it focused on the smugly exploitative aspect of his movies. Indeed, his latest film has even inspired a few critics to unlikely flights of sympathy for the red-state rubes who find themselves at the receiving end of Brüno’s polymorphously perverse assault.

All of this is welcome, though I suspect it has at least something to do with the fact that Brüno, much more than Borat, is an equal-opportunity offensiveness machine. Both films send a foreign grotesque out in search of American grotesques, but whereas Borat was as much a reactionary rube as any of his victims, the mincing, prancing, sex-crazed Brüno belongs to a population closer to liberalism’s heart: He is a cosmopolitan, liberated homosexual. The result has been an extended debate, in the critical community, about whether Brüno is “good for the gays” — and, by extension, about whether it’s good for the rest of us. It took an outrageous gay stereotype, seemingly, to make liberal-minded film critics recognize the cruelty that’s inherent to Baron Cohen’s enterprise.

The irony, though, is that the equal-opportunity offensiveness actually makes Brüno somewhat fairer, and thus funnier, than its predecessor. And it is funny: That much must be emphasized, amid the backlash. Appalling, yes, disgusting, yes . . . but Baron Cohen is an immense comic talent, and his guileless, horrifying alter egos always find a way to drag the laughs out, even when you’re determined to be disapproving. I just hope he realizes, eventually, that the greatest comedians make us laugh with them, and at them — rather than at their unwilling, unsuspecting victims.