Desktops don't abstract CLI commands. Both are different interfaces on the same thing underlying. Both coreutils and Windows Explorer are "abstractions" (as you call them, but they're actually interfaces) on filesystems.
I call it an "abstraction" because that's what it is. Instead of you writing commands manually into the terminal, you use a program that calls it for you and does the hard work. That's what an abstraction is, you're abstracting away something by making an interface around it.
All interfaces, as a matter of fact, are abstractions.