That philosophical point about what it even means to "tell a computer to do things" is a good one. Sure, clicking around in a GUI is also telling the computer what to do. But there's a huge difference between using someone else's abstraction and building your own from scratch. The article is about that second part - the ability to throw stuff together however you want. With a GUI, you're stuck with whatever the designer thought of. With a shell, you can build just about anything