It's a bit more complicated than that.

Rape fantasy and unequal power dynamic fantasy are heavily influenced by gender role expectations.

And while there are similarities in the gender role expectations of Chinese and Japanese societies, there's also a lot of differences as well.

And these differences translates to subtle different tropes and media depictions. Japanese culture has its own distinct part and due to Japanese pop culture, they've heavily influenced culture in China and South Korea as well.

If you were to ask korean bl artists what influenced them, they'll no doubt point to Japanese media as well as other things.

It's kind of like how Chinese/Japanese music have had an impact on Korean music. But Korean music had developed its own distinctness/aesthetic and its popularity lead to influences on Chinese and Japanese music. There's this back and forth influences, not just a one way influence.

Anyways there's other aspects as well. There's a lot of literature examining the role of censorship laws and its impact on explicit content in Japan/China/South Korea. You also have things like how Japanese porn and its tropes are popular in China/Korea and the impact of that, etc.

And of course, you have the complex impact of modern history/politics on culture/media as well.

Anyways, sorry for the essay. Years ago I took and undergrad course that looked at sexuality/consent in Asian media and it all came bubbling back. I just wanted to stress the fact that Japanese culture has its own distinct aspects with its own influences. Just like how Chinese culture also has its own distinct aspects and its own influences.