> EDIT: just to be clear I'm very skeptical there are only two kinds of technical debt...

The author acknowledges this in the article:

  "Of course, there are more than two types of tech debt, but I think the two we talk about here cover a lot of ground."

No taxonomy/segmentation/categorization is perfect, but these structures provide a useful starting point for conversation.

If you believe there's another kind of tech debt, tell us what it is and how it differs from the two kinds described in that article so we can be convinced and expand our understanding of the world!