In anime, manga, Japanese video games etc.
Note: To avoid any miscommunication, I'm more interested in Japans involvement with over-sexualization In Its in pop culture. I accept that It's present in other pop culture around the world, and on top of that, I don't have anything against Japan. I'm just intrigued by the reason behind Its presence In Japanese anime, manga, video games etc.
They are definitely sexualised but to what extent sexualisation is acceptable is subjective.
Look at documentaries like Young Sex for Sale in Japan by Stacey Dooley and films like Bounce Ko Gals, Love Hotel, and Great Happiness Space. They explore the deepest about culturalised underage and female prostitution. Not to mention several available on YouTube. Adult red light districts like Kabukicho, porn, adult anime and entertainment in Akihabara, and female school girl fashion HAS put Japan and kept Japan on the map these days but the fetishism for Japanese women dates back centuries after contact with west Europe and American soldiers. So much so that Japanese women wore literally white face paint on their tan bodies 😂. I know it’s fetishism for the women because Asian men have just become relevant because of the "korean wave" and sex sells and the appeal of the cutesy Japanese woman and girl has given Japan so much tourism and money to their entertainment industry. Expatriates or ex pats are actually called sex pats...
Joshikosei are schoolgirls and you’ll see in the films I listed or if you Google JK Business and enjo kosai what it’s all about. Those girls dressed like dolls holding signs in touring vlogs through Tokyo and Osaka,etc? They’re JK girls. Or pimped out. Facts. Just Google everything I told you. Their mafia has bought out a lot of places in Japanese cities which is why sex clubs and host clubs and JK is legal, and child porn or sexualisaing children and teen girls is unregulated.
You could say the same thing about some K pop stuff but in regards to Japan there is a big love for all things 'kawaii' (cute) which is now very much part of Japanese culture.
In a word: money
Their target market is young males