> Why does that content get ranked highly?
Search engines only show a snippet of the content and that always looks convincing. It's the whole content that is off and, unfortunately, a few seconds/minutes can pass before you realize it (If you ever do).
Well, and Google's proxy read of "quality" might have flawed assumptions. A concise page where you get what you need and leave quickly might read as "high bounce rate".
Search engines track that. It's what a "long click" means. If you click a result, then return fairly fast and keep searching or clicking other links, they infer low quality (for that query at least).