Adam Serwer has written the only thing worth reading on the "controversy":
Wanda Sykes' comedy routine at the White House Correspondent's Dinner was really offensive. In it, Sykes suggested that conservative radio host Rush Limbaugh is supported by Hamas, and that Islamists are "constantly issuing Limbaugh talking points." She joked about terrorists supporting conservatives in general, suggesting that recent violent events in Iraq are attempts by terrorists to swing the upcoming midterm elections in favor of Republicans.
Then she got really personal. She joked that Limbaugh was a racist who doesn't want black people to "escap[e] the underclass." She accused him of being responsible for killing "a million babies a year," and aired her friend's theory that Limbaugh himself was a terrorist attack," a followup to 9/11. She also, most disgustingly, said that if conservatives kept apologizing to Limbaugh, they'd eventually contract "anal poisoning." She wondered when Republicans would finally stop "bending over and grabbing their ankles" for Limbaugh, and finally concluded that Limbaugh was just a "bad guy."
Oh wait. Wanda Sykes didn't say any of these things. These are things Rush Limbaugh has said about Obama or other Democrats in the past year, the kind of statements few reporters found offensive enough to write about, despite the fact that most of them were said with the utmost seriousness. And while Sykes is a mere comedian whose influence on the Democratic Party is negligible, Limbaugh's influence in the party is so great that Republican leaders can't even criticize him without having to issue apologies after the fact.