… on his radio show, says:

Against my own instincts, against my own knowledge, against everything that I know to be right and wrong, I descended to their level [the level of 'the left'] when I used those two words to describe Sandra Fluke. That was my error.

Again, he's apologizing for "those two words" — presumably "slut" and "prostitute".  AND he takes a shot at the left.  I guess he just doesn't know how to apologize.

Does he apologize for saying that Fluke is "having so much sex, it's amazing she can still walk", or that Georgetown should establish a "Wilt Chamberlain scholarship … exclusively for women", or for describing Fluke as "a woman who is happily presenting herself as an immoral, baseless, no-purpose-to-her life woman. She wants all the sex in the world whenever she wants it, all the time, no consequences. No responsibility for her behavior", or any number of other things?

Nope.  Just for the WORDS "slut" and "prostitute".

And here's the real question: if calling her those names was against his own instincts and everything he "knows to be right and wrong", when exactly did he realize that?  Was it on Day One?  Or Day Two, when he doubled down?  Or Day Three, when he doubled down again and attacked her?  

If it takes a man four days to realize that calling a woman a "slut" on the national airwaves is wrong, he's immoral.  He's without values, and his claim of an apology, is false.

And he's not sorry.  We KNOW this from… well, this exchange from November 2007, when a caller reacts to Limbaugh commenting that “I’m like a woman when you get to numbers. I don’t follow them too easily”:

RUSH: I had a Barbie doll once, Cheryl, and you’d pull the string on the back, “Math class is tough.” You know the stereotype. I was just making a stereotypical joke.

CALLER: Oh, my goodness, I can’t believe you said that. I really can’t. We laugh at you all the time, but that was not funny. That was degrading to some women. […]

CALLER: Okay. Do you apologize to the women? (Laughing.)

RUSH: Well, you know, Cheryl, I have to tell you, Cheryl is one of my all-time top-ten female names, and I hope that I can salvage your loyalty here as an audience member. I’m not going to apologize. People in my position never apologize. But we just acknowledge that you were upset and offended by it. I’ll apologize you were offended.

CALLER: Okay.

RUSH: But I’m not going to apologize for saying it. I meant to say it. Why would I apologize for something I meant to say? It was a joke.

CALLER: Okay. I guess. Okay.

 How else do we know he's not sorry?  Even as he tried to take those two words back, Limbaugh made more controversial comments. Among other things, he speculated that Fluke had "intentionally target[ed]" Georgetown to get the school to provide contraception, and said that she had provided "inexpert testimony" to Congress which consisted of “vague examples based on unnamed friends."

UPDATE: According to ThinkProgress count, Bonobos is the 10th advertiser to drop Limbaugh in the wake of his sexist and hateful attacks on Sandra Fluke.