If you want a serious answer, aggressive urbanization is a plague. If you put millions of humans in a condensed and compact location, out of boredom and apathy, they'll start devolving into hedonism and sexual deviancy. I don't know how much of Japan is urbanized, but a lot of it is and, as a result, a lot of people there live like bugs working for a corporate hive. Humans that are overworked or live incredibly boring lives in a compact environment have to turn to stimulants like drugs, junk food, or, surprise, sexual stimulation. Socialization also goes to die in urbanized locations, which is ironic given that so many humans live compactly together, so loneliness also leads to stimulant addictions and, let me tell you, Japan's biggest export is loneliness. Marriages are rock bottom low and a lot of the Japanese commit suicide out of grief of their lonely, unsocial lives.
Pedophilia is only one big symptom of the larger problem going on in Japan. Japan is addicted to stimulation whether that be through sexual assault, lolicon, or hyper-objectification of women. I don't know how their drug problem is there, but it's probably pretty bad given that drugs are usually pretty common in urbanized locations in the USA. Stimulation addiction happens when people get lonely, get overworked, get pessimistic about their outlooks on life, and become compact like sardines in large cities like Tokyo and Hiroshima.
This is a really big fucking problem in Asian countries right now; they never find a middle ground on anything. It's always one large extreme or the other. It's why China is so backwards, it's why South Korea has been stagnating, and why Japan's birthrates are low and suicide rates are fucking astronomically high, and why Singapore is currently facing a crisis in demographics.
