The authors number one recommended book is ~166 pages in total. I skimmed through and it's mostly pictures. The blog also contained no data. This is all completely fine, but it rubs me the wrong way when things are posed as scientific or rigorous, but are mostly subjective opinion pieces. I like to see what "thinking in systems" gets me with real evidence. I appreciate they took the time to create and share this thou…
You are seeing a few parts (titles, maybe a paragraph or two, a sample of the diagrams and pictures) and you are not seeing the system behind it. You have to read it whole to properly understand its point.
And as that system is not isolated from the world, after you understanding it you will get a good hint of the outer system, things that are happening in the real world outside of it.