I think they understand that. They're saying they dislike TUIs and prefer CLIs because CLIs are composable.

> and GUIs have never been composable.

Sure they have, or at least it has been tried. I think it turns out to be such a hard problem to solve that it degrades into proper programing much faster than a cli where pipes can carry hard.

Some examples:

The first xerox alto interface.

smalltalk

Microsofts OLE