They didn't bother outlawing possession of CP until 2014 https://edition.cnn.com/2014/06/17/world/asia/japan-child-porn-law Distribution was legal right up until 1999
Under the new law, people in possession of child pornography have one year to dispose of it before they risk prosecution.
Very considerate!
See my other comment examining where the top 10 instances by userbase get their funding from and how well they're doing
Not to mention that over the years there have been a lot of instances that have gotten into a variety of precarious situations that could have been avoided or alleviated if they had a lot more money.