I honestly had no idea they all started with an R will vote when I come back from school.
Actually, to further it more, they all start with "Re-", and some say it's because it's a reference to "Recovery", which is what the Twelve-Step programs are about, recovery from addiction, compulsion, or other behavioral problems.
Oddly enough, "Recovery" wasn't used as one of the titles, but I suppose the WHOLE thing is about "Recovery", so it'd be redundant to label a single step/movement with that title.
-Marc.