I guess, "there's effectively a game in the market with our same branding and IP, allowing people to access only the scenes in our dating sim they want to, turning it into a different kind of application with deleterious associations to our brand" is a theory of harm I can grok. I don't think it would hurt short term sales in this particular case, but that could hurt the brand and thus long term sales. I have trouble parsing the rationale because it seems very anti-consumer, at least with this being my only exposure to Japanese law, but that probably wouldn't have flown in the US either.