Anybody who works for ratings -- meaning, they work for advertisers -- is an entertainer. They're all entertainers. All of 'em. Some people entertain with politics. Others with fart jokes. Jon Stewart does fart jokes about politicians. Some people take their jobs more seriously than others -- not all are worth ignoring -- but it's haggling over a fine that can't be well defined and therefore isn't worth defining.
This desire to separate Rush Limbaugh from the rest of these guys is out of sheer embarrassment, like how the English always make sure to note that Andy Murray is Scottish when he loses. Lots of voters listen to Rush and therefore the politicians have to watch their step. I'd be embarrassed too, if I had to do that.