Problem with your stigma theory is that it only exists to people who actively play the game and have for a while - if a Nintendo employee were to download it and take a look it’s not something they’d pick up on. There is literally no “stigma” surrounding Graal, just players who think the dating scene is weird. Every kids game with an open chat room experiences the same thing as Graal.
Also, Graal 3D is a separate game - so nothing in iClassic is even relevant (which means if this ‘stigma’ existed it wouldn’t even matter). Most game moderators don’t get paid on other games either, a lot of MMOs similar to Graal make use of volunteers.
The problem with Graal and Nintendo is just a legal issue and nothing more, factoring in that Nintendo once filed a lawsuit (or threatened too - essentially the same thing in corporate eyes) against Graal would most likely be the only reason they don’t publish it (if it passed other requirements for publication on the Switch).
It doesn't take long for anyone to see that this game is mostly about customizing your character and chatting which in turn also shows the whole edating scene and how that can negatively impact kids quite easily.
I'm not saying this is a huge issue as like you said, it happens on like every kids game with an open chatroom and there is some form of moderation to prevent bad situations, but the difference is whether Nintendo is letting said game on their platform or not which they obviously would rather not.
Also, yes, I know most games have volunteer moderators but they tend to have a proper paid team of employees dedicated to handling user support, reports, and going more indepth on what punishments to give people as moderators in games normally have minimal powers as they shouldn't be trusted to be the final decision maker due to them being nothing more than volunteers.
As far as I know graal doesn't have a dedicated team of employees like this and mostly depends on volunteers to handle like every job below global admins & devs.