General discussion of illegal activities is legal, but distributed methods/keys/software to bypass DRM is not. In addition to the poster getting in trouble, the admins of multiple instances could at minimum be forced to delete the content, and at worst get their asses kicked by Nentendo’s legal team, and be forced to reveal the identities of the user that posted it.
They will delete it if they get a DMCA takedown request, as required to avoid liability under US law. They don’t however proactively look for copywriten content. As long as the music owner doesn’t care or doesn’t notice it will be fine.