To avoid confusion! If all deserts had the same name, nobody would know what area was being referred. Were they referring to a desert in China or in the United States?
Japan has no deserts.
There are no deserts in Delaware.
Haiti has no deserts.
Honduras has no deserts.
There are no deserts in Rome.
Alaska has no true deserts.
Alabama has no true deserts.
Yugoslavia has no deserts.
Haiti has no true deserts.
There are no deserts in Kentucky.
Kentucky has no deserts.
There are no deserts in Ireland.