If you read the first paragraph from the page that I had linked, you'll see what "Sacred Geometry" refers to..
The term "sacred geometry" is used by archaeologists, anthropologists, and geometricians to encompass the religious, philosohical, and spiritual beliefs that have sprung up around geometry in various cultures during the course of human history. It is a catch-all term covering Pythagorean geometry and neo-Platonic gometry, as well as the perceived relationships between organic curves and logarithmic curves.
That's one of the best definitions that I've found. Ask an archaeologist why they've decided to call it that, as I'm not the one who coined the term. But as it IS the term used to describe ancient geometry and mathematical relationships, that's the term we're stuck with.
What I want to know, how does this prove or disprove crop circles?
I don't know if it can be considered a proof of crop circles, but it does prove that whoever is creating them knows Sacred Geometry and the importance of the Golden Ratio.
A little more info...