During President Bush's term there were a number on the left who used the medium of movies television and print ads who pushed the bounds as far or further than Rush. Some even having veiled recommendations for Bush's assassination(There was a movie regarding this). "Comedy" was used as a medium for some of the most vile insults. Heck one comedian even hoped for Rush to die. There is no reason that we should give them a pass for their brand of hatemongering because it is wrapped in a comedic routine. It's all entertainment. People like Rush, O'Reilley, Hannity, Savage et al are entertainment. They may not be your entertainment, but they are none the less. They are also listed as opinion from the start.
Quite frankly I'd give them more of a pass simply because you get exactly what you expect from them. Those who watch/listen to them are almost always already of the same opinion. But when watching regular TV shows, you get the agendas of the actors/producers/writers thrown in. The hidden hatemongering being more likely to get someone to act. Their hate is wrapped in a pretty package. Opinion shows are like the generic form of hate.
"I would rather be exposed to the inconveniences attending too much liberty than to those attending too small a degree of it." Thomas Jefferson