Coming from a data engineering and business analytics background, the terms "structured" and "unstructured" seem to be swapped in meaning here.

I'd expect to talk about anything in a DB as "structured data". Flexible serialization formats such as JSON or XML are "semi-structured". And something from e.g., an office document is "unstructured".

This is not a complaint or criticism. I understand the article just fine. It's just interesting how different perspectives can affect what words mean (: