The people excusing Rush Limbaugh as a satirist are missing two crucial differences between true satire and playground-bully mockery: irony and justice.
Irony provides the essential distance that marks comedy from cruelty. It's been said that comedy is tragedy sped up and exaggerated to the scope of farce, but if Limbaugh truly is a comedian, his jokes fall flat from lack of irony and justice in scope. Satire mocks the powerful from below; if a powerful person mocks someone less powerful, he's simply being an asshole.
Making fun of physical handicaps (as Limbaugh has done) is the lowest form of comedy unless there's ironic inversion and justice involved. Otherwise, it's like pulling wings off flies to get a laugh. Stephen Hawking can make a cripple joke because he's clearly handicapped himself. When Jewish satirist Sasha Barton Cohen gets a roomful of people to sing "Throw the Jew Down the Well," he's employing satirical irony; Limbaugh would not get the same kind of license to make an identical "joke" unless he was singing about killing fat pill-popping bigots. Now, if Rush was a liberal assuming an exaggerated right-wing persona (like Stephen Colbert), he'd be using satirical irony. If Limbaugh is anything other than what he pretends to be, however, he's been hiding that fact for over 20 years.
Meanwhile, the principle of justice marks another line between satire and cruelty. Female satirist Sarah Silverman can get away with making rape jokes (barely...) because she's clearly not a rapist. When overtly masculine Andrew Dice Clay made them, even through his exaggerated persona, such "jokes" became a career-limiting move. People can laugh when a mouse gives an eagle the finger; if the eagle gives the finger to the mouse, there might be a brief laugh of pure shock (like when George Carlin made rape jokes about Porky Pig raping Elmer Fudd... yet another ironic inversion). If the eagle continues to eat the mouse afterward, however, it takes a hard-hearted person to continue laughing.
At the beginning of his career, Rush did have some valid targets, and he applied a bit of wit to them. His "feminazi" rants held some justifiable sting in the early '90s, when college campuses were imposing "speech codes" and N.O.W. was staging book-burnings for American Psycho. (A book whose incredibly dark satire became more obvious when it was adapted by female filmmakers.) Using the "Born Free" theme to counteract the spotted owl controversy was sort of amusing at the time... provided you didn't think too hard about how that controversy revolved around the idea of wiping out a whole species for profit. Thing is, Rush has since become the eagle [1], and yet can't still can't resist the impulse to give a mouse the finger as he eats her. And when the powerful mock the powerless, that's not satire - it's just cruelty.
While it's true that straightforward mockery CAN be an element of satire, that's a clumsy, short-lived approach. (cf. Andrew Dice Clay) Obviously, the schoolyard bully has an audience who laughs when he pulls down an honor student's pants... but really, how many of them are still laughing when they've grown to adulthood, and how "adult" do we find such people once high school ends?
Limbaugh has since presented a half-hearted apology [2], claiming the satirist's cloak of protection. "For over 20 years," he stated, "I have illustrated the absurd with absurdity." The target of his absurdity, however, reveals the truth of Rush's position: rather than comment on the absurdity of a lone female finally being "allowed" to testify before an all-male congressional committee regarding female contraception [3], he chose to slut-shame women who use contraception. But when even the eagle - most ironically, one who's been caught having his own issues with drugs and legalities - makes such admissions, it's worth asking where the true absurdities within the social issues lie.
As for a career defined by pulling the wings off of flies to get a laugh, it's a poor comedian who does so just to show why insects shouldn't aspire to fly.
--------------------
1 - As a prosperous straight American white male of supposedly Christian convictions, Rush has really ALWAYS been the eagle; it's easy to understand, though, how his audience felt persecuted by the likes of Molly Yard and Andrea Dworkin, regardless of who really held the power in society as a whole.
2 - ...part of which is belied by the actual transcripts of his show.
3 - At a time of staggering economic woes and severe international strife, Congress has nothing better to do?