We don't have a lawyer to ask, but as far as I'm aware, videos of sum random dude masturbating to and ejaculating on legal and non-sexual photos/videos of children does not constitute as child pornography in and of itself in the US. It might constitute as "obscene", but nobody really gives a shit about obscenity - it just gets thrown in there for good measure when people are convicted for more tangible things

For what it's worth, 8chan (which started as an "anything goes as long as its legal" site) B& any kind of photo or realistic image of children in a "sexual context". "Sexual context" included the user's own comment, as well as the nature of the board it was posted to. E.g. a simple reaction image of a child would be fine on /v/, but would be B& on a NSFW board or pedo discussion board. Any kind of revealing/skimpy clothing, "child modeling", etc. was B& regardless

Personally, I'm in favor of Heyuri banning images/videos of 3D loli in "sexual contexts" and material that's obviously designed to arouse the viewer (which would include a lot of junior idol and child modeling material), while still allowing the kinds of thing you might find on Instagram, on stage, or in a clothing catalog (as long as the poster isn't st00pid enough to inform everyone they're aroused by it or are fapping to it). It'd make moderation a lot simpler and prevent the inevitable trouble that hosting such material always causes when the wrong people find out about it

I've recently brought the topic up with kaguya however, and it seemed he was more in favor of keeping as much 3D loli material as viably possible - that's why there's been less moderation on it lately