Why should it be required to support any other filesystem other than its own? It's a single OS and utilities, not a general-purpose OS (or filesystem) management tool. It does what it needs to do for the overwhelming majority of users that choose to use it, and more than most of them will ever require.
While what you ask for may be useful to a handful, is it really justifiable for the development effort involved, and the likely costs associated with it?
Or are you just stirring the pot?