I don't know if it is ai generated or at the opposite hand written a little bit fast but I find this article very hard to read despite the concepts in it being simple.
Where LLMs can be really actually quite useful, is situations where you have a lot of context and want to distil it. That's what I think happened here: the author has a lot of information to convey, and the LLM-generated output is relatively information-dense.
Unfortunately there's no objective measure for information density of an arbitrary piece of text.