The wording „designed for nodes“ is perhaps unfortunate, as this may not be the case in the historical sense. However, I am at a loss why one should see anything in XML but nodes.
XML is an expression, nodes are the value. I think this is the essence of understanding XML.
What people thought 15 years ago when finishing the XML spec is irrelevant. To dwell on that appears to me pure pedantry. People thought, once, that the earth is a disk, but we have passed on in the mean time.
In my opinion, XML is not syntax backed by a data model. It is a data model, augmented by a syntax.