https://nichegamer.com/dlsite-temporarily-blocks-major-western-payment-processors/
A few of the articles on this site can be a bit on the conservative side but there is good material like this.
This is extremely concerning for free expression. The art / sexual expression (of people who don't exist) shouldn't violate Japanese law and it should be covered by the First Amendment (although, it's not America).
The Japanese Constitution also gets brought up a lot, for example:
"Article 19. Freedom of thought and conscience shall not be violated."
"Article 21. Freedom of assembly and association as well as speech, press and all other forms of expression are guaranteed.
No censorship shall be maintained, nor shall the secrecy of any means of communication be violated."
From what I've seen, this right is not absolute. If someone deliberately posts non-consensual porn of someone (someone who actually exists), for instance, it wouldn't protect them from the law. However, that is a very different kind of case.
I thought you might be interested in this case.
@olives best thanks for the tip, it's a bit too niche for me, but i appreciate you letting me know!