Back around 1991, a friend and I decided this song was about a drug-dealing pornographer from a parallel universe, which also has a Leatherhead. We were fueled on Philip K Dick, Williams S. Burroughs, Hellblazer comic books, David Lynch, and living in a backwards, creepy Southern Gothic town in which our Clean Steve would be a natural inhabitant.
Whatever Hitchcock was actually going on about will forever be irrelevant to the character we thought he was sketching back then.