Let me throw out a few questions and thoughts.
If the characters in these games were very obviously fully-grown and adult women, and the discussion is pretty much in line with the previous Criminal Girl threads; in that they mostly involved discussion about the sexual pandering parts and "this game is for pervs/why does this exist?" would the moderation team object people to making threads about the game?
Is the issue here that the characters look like children or that there is sexual pandering and that's mostly what is being discussed?
I personally find the sexualization of children and teenagers that is present in a small number of Japanese games (Hyperdimension Neptunia etc) to be, well more than a little creepy, but it's obviously there for a reason and it does not seem like it's going to stop.
For example
there's a scene in Persona 3 (Fantastic game IMO) that some people would argue is more than a little eyebrow raising.
As long as stuff like this is in games then this is going to be an issue and people are going to discuss it, whether that be in disgust or approval. Banning discussion on certain games outright is a very blunt and imprecise way to deal with the problem and sets a very bad precedent for the future.
I understand that the moderation team does not want to deal with threads involving arguments about pedophilia or threads that have lots of NSFW images posted, but I would argue for clear cut rules that allow for discussion of the game as a whole, but not the controversial and thread derailing conversations within.
Something like "If a game has scenes of a (particular) questionable nature, please refrain from posting images or video of these scenes or derailing discussion so that they are the main topic.
and to back that up if mods don't want discussion of a certain subject like pedophilia as it leads to shit threads:
"Do not makes threads solely discussing scenes of a (particular) questionable nature within a certain game"