An exposé by China's state broadcaster on rampant prostitution in the country's "sex capital" Dongguan triggered a huge police operation -- as well as a surprising online backlash.More than 6,000 police officers swept through hundreds of hotels, saunas and karaoke parlours in the city, in the southern province of Guangdong, arresting 67 people, shuttering 12 venues and suspending two police chiefs, state media said.The raid came hours after a Sunday night report by China Central Television (CCTV) detailing the extent of the prostitution industry in Dongguan, an industrial hub where by some estimates as many as one in 10 migrant workers are involved in the sex trade.Filmed using hidden cameras, the half-hour long CCTV programme showed young women lining up in rooms and on stage at several venues, talent-show style, while an undercover reporter inquired about the prices of each.The programme showed a reporter making two phone calls to local police, but each time, an officer failed to show up at the scene."Will the police come?" the reporter asked a brothel worker at one point."Don't worry about the police," the worker responded. Yet while authorities responded to the programme with a "three-month crackdown" on the sex trade in the southern city, China's Internet users heaped criticism on the state broadcaster, with some arguing that it had focused more on shaming the women involved rather than on addressing the root causes of the sex industry."Don't cry, Dongguan! CCTV is ruthless, but the world is full of love. Hang in there!" read one popular message on Sina Weibo, a Chinese version of Twitter.Chinese Web users -- who typically post images of red candles online to show their sympathy for victims of natural disasters -- shared images of red condom-shaped candles Tuesday in the wake of the Dongguan report.Others mocked CCTV for sending undercover reporters to reveal an industry that is obvious to any visitor in Dongguan, and likened the report to a similar "exposé" last year by the broadcaster exploring whether Starbucks was overcharging Chinese consumers.