Gruber is constrained by both decorum and tradition — Jackass of the Week is a running series, after all — from calling Limbaugh something harsher. I, however, am not. “Asshole” comes to mind, of course, but the term’s been bleached a bit by overuse. “Scum” seems short, sharp, and to-the-point.
This, to use Lois McMaster Bujold’s expression, “is not news“, but it bears periodic repeating anyway.