Thanks for your Feature-Request. Iโd like to add, that the object menu would be the perfect place, as the state object is already living there. The only thing you canโt do at the moment is to change it there.
This should get more attention. I already got my states working but like @MrGeneration said - itโs already living there. Why not make it manageable too?
The problem might be that we need to protect the default states as you might seriously damage things with just removing stuff. I guess that this is not implemented in core yet (and thus protected on GUI)