Fair point with respect to the separate topic. My apologies.
As for the automatic cleanup bit, perhaps the article is trying to focus purely on the mutex types themselves? Or maybe they included the "when you lock" bit to emphasize that you can't forget to unlock the mutex (i.e., no reliance on unenforced idioms). Hard to say given the brevity/nature of the section, and in the end I think it's not that much of a problem given the general topic of the blogpost.
As for the automatic cleanup bit, perhaps the article is trying to focus purely on the mutex types themselves? Or maybe they included the "when you lock" bit to emphasize that you can't forget to unlock the mutex (i.e., no reliance on unenforced idioms). Hard to say given the brevity/nature of the section, and in the end I think it's not that much of a problem given the general topic of the blogpost.