You're free to argue whatever you want, but claiming that a file system should have folders as the parent commenter did, or support specific operations, seems a

You're free to argue whatever you want, but claiming that a file system should have folders as the parent commenter did, or support specific operations, seems a bit meaningless. I could create a system not supporting folders because it relies on tags or something else. Or I could create a system which is write-only and doesn't support rename or delete. These systems would be file systems according to how the term has been used for 40 (?) years at least. Just don't see any point in restricting the term to exclude random variants.