[andrewfong]

They sort of do. Each patent has both a description, written in more or less understandable terms (and often including diagrams) and the claims, which is what the post references (e.g. "a system or method ..."). The point of the legalese in the claims is to explicitly define the boundaries of the patent. By way of analogy, imagine if you had to describe the boundaries of a piece of land you owned, but the land wasn't a regular shape and you couldn't rely on a map.