Music education is in general great at telling people what notes to play, but rather worse at supplying much intuition for why certain patterns of notes work together.

You can look at a diagram that will tell you what notes go together to make a particular 11th chord, say, but it tells you nothing about why that's a useful way to combine notes.

The blog post is aimed at people who know some of the "what", but who could use a clue as to some of the "why".