So actually, your comment's actual data is in your grouchysysadmin.com instance, and similar to following a symlink, lemmy.ml is just pointing to your data.
If I host an instance and disable community creation, and my users comment & post in lemmy.ml communities, I still have to mod those comments in lemmy.ml even though I'm not a mod in any lemmy.ml community?
What about the mods in lemmy.ml communities? Can they still mod content made by my instance's users?