Isn't pedophilia the obsession and or desire toward young girls?
Pedophilia is a psychological disorder in which an adult experiences a sexual preference for prepubescent children.
Most of the junior gravure idols are at ages lower than 16. Some if not most of them are put into positions where they're dressed or pose in sexually suggestive manners. Of course, you can argue that it varies by the reader's perspective, but really, what's a 12 year-old doing in a bikini lying on a bed. Questionable actions? I think so, but like most people had argued that this "alternative outlet" is better than having men actually kidnapping little girls and raping/molesting them.
Same could be applied to pornography versus prostitution, it is an alternative outlet. It may be illegal if viewed by someone who gives a damn, but when it comes down to pornography, no one can say no (unless you're the holiest of all priest and the cleanest of all monks).