I think you're right about the basics of what a CDS is, but this doesn't really cover it. You also need to understand how the price of a CDS moves and why. Which can lead to much more complicated systems.
You're right, of course, but my point (and maybe I didn't make it very effectively) was that to acquire a similarly thorough understanding of macros would require way more information - I wasn't trying to make the point that a complete description of CDS could be given in a couple of paragraphs.