Gruber’s recent article, Anti-Anti-Aliasing, is very effective in that — besides being a good, easy read about a complicated subject — it addresses the actual problem with Safari (the API’s) rather than launching a salvo against Safari itself. Regardless of the cause, the problem (font’s being anti-aliased despite the designer’s desire for them not to be) is a bug and should be treated as such.
Again, consistency is the issue here — consistency with the OS, consistency with other browsers, consistency with the general concensus that should be adhered to when rendering fonts anywhere.
Designers make certain choices regarding font selection and size based on how they anticipate them to be displayed. In other words, the Narrator chose Geneva (which defaults to Arial on Windows) and sized it a certain way so that it would perfectly fill the link bar at the top of this page (as mentioned in Gruber’s article).
The link-bar font and size was selected specifically so that it would not be anti-aliased. The font is displayed correctly in just about every browser (including browsers running on Windows and Linux) except for Safari. While the browser might not be to blame (the API’s are), it bodes poorly for Safari, which is otherwise the best thing since morning coffee.
Despite that fact, the Narrator will continue to use Safari as his primary browser, even though he feels pain each time he sees something like this.