He's not really the moderator for those magazines. Those are communities that exist on Lemmy instances. For some reason, the actual community owner/mod list doesn't get synced over to Kbin from Lemmy communities. His username shows up as the "owner" for those, presumably as a failsafe for a null entry in the community owner metadata.
EDIT: Actually, these accounts are just spamming the local Kbin magazines, in which case yes that is something that should be moderated from the Kbin side.