The thing that made it not obvious was that the comedian they "stole" the routine from was some low rent guy doing the club the circuit. There's tons and tons of comedians out there most of whom never develop a serious national audience, cruise through the Comedy Central Presents listings sometimes, notice how you probably don't recognize the names of any of them, and they're just a small fraction of the working comedians out there. But you can garauntee that if any of them saw one of their routines word for word on SNL without being paid for it they'd sue NBC.
I like Sorkin's writing, even the West Wing when he wasn't being a dick about his politics was good (problem is he was a dick way too often). Most of his characters are smug and self-congradulatory, they also tend to be wrong even within the structure of the show. Actually pretty realistic, most people operate from an assumption of being right, and if there's a throw down on it will climb on their high horse. So far in Studio 60 he's gone more back to his Sports Night days, much less overt politicizing, pulling much more from the insanity of trying to put on a live TV show and the people drawn to that kind of work.