From a reader:

Jonah,
Your analysis of the non-rightwing nature of Darth Vader’s history contains a clear terminological error. So far as I can tell from episodes 1-3, “Darth” is not a name but a title, indicative that its bearer is one half of the then-extant pair of Sith. Hence, Darth Maul [who has no other identity we know of], Darth Tyrannus [aka Count Dookoo] and the Emperor Palpatine as Darth Sidious. Darth is the equivalent of “Sir” or “Lord” (or “Dark Lord”).
Don’t feel bad, though: Obi-Wan Ben Kenobi makes the same error in Episode IV.

Me: Point taken. However, the Count on Sesame Street is often called “count” as if it was a first name too. And his dialogue is often better written than the junk we heard in the last couple Star Wars movies.