They [patents] aren't written in normal legaleze. I worked at a company that submitted a patent for a device I helped design and build. We submitted technical documentation, and the company lawyers turned that into a patent document. When I reviewed the patent, I would have had no idea that the patent was describing what I worked on, had they not told me so ahead of time. I'm not joking. What was about 20 pages of documentation of a concept, including illustrations, became hundreds of pages of completely confusing information. Where a single technical term was the precise meaning of something, it would be replaced with entire paragraphs explaining that concept in a way that no engineer would understand it.
Patents are technical documents. They are supposed to describe a solution to a problem in a way that a technician with adequate knowledge can understand the concept and verify that it is not already in use, and that a future product does not infringe upon it. If the designer of the system does not even recognize the patent, then it is not able to do that.
You are correct when you say that legalize has very precise meaning. But patents are intended to be as broad as possible, so the lawyers do what they can do take a single concept and make it as vague as possible. So words that have precise meanings in the original technical document are replaced with vague meanings (hence how single terms become entire paragraphs). I actually saw sentences that spanned whole pages, and paragraph separators were used to indicate that this "word" had been explained inline.