Wild Weekend's Hangover: Outrage Follows Japanese Tourists' Orgy With Chinese Prostitutes. John Pomfret gives some context:

Prostitution and sex tourism are huge businesses in China, played out almost in public. Practically every hotel, from no-star dives to five-star international chains, boasts a bevy of women offering oily massages and more to travelers.
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Incidents involving Japanese in China invariably take on an incendiary quality, with the Chinese quick to take offense and the Japanese just as quickly arguing that they are being singled out unfairly.
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Many Chinese believe that Japan's efforts to apologize for its wartime behavior are insincere. And to this day, Chinese continue to cope with the remnants of the war. Last month, one construction worker died and several others were badly burned when they unearthed a batch of mustard gas that the Japanese occupation had left behind.

In recent years, China's Communist rulers have nurtured anti-Japanese feelings among their people, according to Gilbert Rozman, a professor of sociology at Princeton University. He said that since the mid-1990s, Communist Party officials around then-President Jiang Zemin decided to use resentful nationalism as a unifying ideology to replace the communism that few believed in anymore. The government also has routinely played down any mention of the multibillion-dollar flood of Japanese aid and low-interest loans into China.

This treatment led to a backlash in Japan, where polling data, starting in the mid-1990s, began to show a dramatic rise in opposition to China. Chinese polling data reflect the same trend, with respondents routinely listing Japan as by far the No. 1 potential enemy of China.

First of all, prostitution is rampant in China; as the article points out, often with help from the Chinese security services or police. See also Peter S. Goodman's Sex Trade Thrives In China, not to mention how A village was transformed by organized prostitution.

And as I've said before, the Communist Party is probably responsible for far more deaths than the Japanese were. But that's OK. It was Mao's responsibility, and he's a "great man".