Why didn't the mainstream media jump all over McCain calling his wife a cunt?

I generally leave the political blogging to those who are solely dedicated to it, but this does involve one of Arizona's very own and it's really not so much about politics as it is about feminism. I couldn't sleep last night because I was thinking about this question:

Why didn't the mainstream media jump all over McCain calling his wife a cunt?

The following excerpt is from The Real McCain by Cliff Schecter:

Three reporters from Arizona, on the condition of anonymity, also let me in on another incident involving McCain's intemperateness. In his 1992 Senate bid, McCain was joined on the campaign trail by his wife, Cindy, as well as campaign aide Doug Cole and consultant Wes Gullett. At one point, Cindy playfully twirled McCain's hair and said, "You're getting a little thin up there." McCain's face reddened, and he responded, "At least I don't plaster on the makeup like a trollop, you cunt." McCain's excuse was that it had been a long day. If elected president of the United States, McCain would have many long days.

The reason why I think this story may be true, is because McCain was confronted about it by a Baptist minister on tape at an Iowa town hall forum in May and he didn't deny it. Here's a link to The Huffington Post piece on the subject and a video of McCain being asked the question and his reaction.

But my concern is not really with the truth or McCain. My concern is with a double-standard. Why is it that the mainstream media will engage so gleefully in other types of smear campaigns, (“We live now in an era where everything and everyone is fair game,” recently stated Douglas E. Schoen, who was a pollster and adviser to former President Bill Clinton from 1994 to 2000.) Yet when it comes to something so damaging to women, nearly everyone is willing to look the other way? As far as I know, the Cunt Incident hasn't been touched in television, radio or mainstream print media. It was surprising to me to stumble onto the story online.

On one hand we could respond to this question as did a good friend of mine who is also an excellent journalist: "No mainstream media can write about it because they can't confirm it; these are anonymous sources and the material is too inflammatory to print without people willing to put their names behind it." But to give a specific example of the double standard I'm perceiving, consider that CBS news is reporting about Michelle Obama "allegedly" using a derogatory term for white people ("whitey") but no one so mainstream can be found mentioning McCain "allegedly" calling his wife a "cunt".

No one jumped on McCain for calling his own wife the most derogatory of slanders against women? Really? Why didn't anyone play Arnold Assgrabber's video above (and other similar clips) more often when he was seeking office? Does the mainstream media assume that this brand of sexism is perceived as irrelevant by the public? Is it? Or is the mainstream media afraid that they will come under fire for reporting in "bad taste"? Isn't that a guise for skirting the issue? (No pun intended)...