The usual Japanese talking point is that CSAM laws exist for rights and wellbeing of kids, which are real human being. If it's used/defined for cases that are not plausibly harmful to kids, such as some adults doing some things nowhere near kids using none of real materials, then it's often argued that the law is abusively defined/used, and/or plain broken. That talking point, incidentally, should logically validate against texts of laws, though sometimes it may not with the intents between the lines like you've brought up.

But that logic usually align perfectly with the texts of laws. Those laws aren't supposed to be adult pedos beating and correction laws. They're not pedo soft landing laws either, they are supposed to be parts of younglings protection laws, globally. Technically that should be all that matters. So there's that.