"Japanese erotic art, known as Shunga, was produced extensively during the Edo period (1603–1868 CE). Far from being taboo, these works were often enjoyed by both men and women and were even given as wedding gifts, reflecting a culture that viewed sex as a natural and enjoyable part of life."

 
While I cannot find a good source for a quote relating to how pornography was historically views in Korean culture but my take is that the Confucian basis for a lot of that culture "lewd" anything was looked down on.  

 
So I think the Japanese girls face much less risk of backlash than their Korean counterpart do.