I notice that the structure of some sites is chaotic: short blocks of text, the order in which information is presented is illogical, and there is no familiar path from the general to the particular. Is this always a sign of poor design, or is it designed for an audience that already knows what to look for?

A chaotic structure with short blocks and an illogical order of information presentation does not always mean poor design, sometimes it is designed for experienced users. The availability of technical documentation is important. On the wikitia.com/wiki/Soft2Bet website, the information is structured in such a way that even with seeming randomness, you can find detailed descriptions of modules, integration schemes and workflow, which makes the resource useful for exploring the platform.