On April 4, shock jock Don Imus called the Rutgers women’s basketball team "nappy-headed hos," and was soon fired.  Last week the Washington Post noted:

Two weeks past its news expiration date, the debate seems to be gathering renewed strength.  .. On Monday hip-hop mogul Russell Simmons, who just two weeks ago was arguing for the rights of rappers to express themselves as artists, did a seeming about-face and called for the voluntary banning of "bitch," "ho" and the N-word from the lexicon as "extreme curse words." 

Monday we heard:

A panel discussion titled "Does Hip-Hop Hate Women?" drew more than 400 people indoors on a sunny day — a sign that the furor that erupted over Don Imus’ comments isn’t over yet.  As Imus struggled in vain to keep his job earlier this month, he claimed that rappers routinely "defame and demean black women" and call them "worse names than I ever did." Some speakers criticized music executives … Others … said hip-hop shouldn’t be made a scapegoat for what’s wrong in America.

James Poniewozik asked the key question on Time‘s April 12 cover: "Who Can Say What?"

A few months ago, I interviewed [Sarah] Silverman, who argued that her material was not racist but about racism (and I agree). But she added something that surprised me, coming from her: "I’m not saying ‘I can say nigger because I’m liberal.’ There is a certain aspect of that that I’m starting to get grossed out by. ‘Oh, we’re not racist. We can say it.’" …

Of course, assessing Imus’ show is a subjective judgment, and setting these boundaries is as much an aesthetic call as a moral one. It’s arbitrary, nebulous and, yes, unfair. Who doesn’t have a list of artists or leaders whose sins they rationalize: Elvis Costello for calling Ray Charles a "blind, ignorant nigger," Eminem for peppering his lyrics with "faggot," Jesse Jackson for "Hymietown," D.W. Griffith for lionizing the Klan or T.S. Eliot for maligning Jews?

You might say that there’s no excuse and that I’m as big a hypocrite as Imus’ defenders for suggesting that there is one. Which may be true. That’s finally why "Where’s the line?" is a misleading question. There are as many lines as there are people. We draw and redraw them by constantly arguing them. This is how we avoid throwing out the brilliance of a Sacha Baron Cohen – who offends us to point out absurdities in our society, not just to make "idiot comments meant to be amusing" – with a shock jock’s dirty bathwater. It’s a draining, polarizing but necessary process.

That Post article also noted:

The question of hip-hop’s culpability in the Imus issue is one that some rap-industry figures appear reluctant to address. Label executives and radio programmers on both coasts repeatedly declined to comment for this article. …

"We can’t continue to embrace the ‘Do as I say, not as I do’ mind-set. It never works. . . . We need to turn the mirror back on ourselves and see if we’re participatory in our oppression," said Asha Camille Jennings, a New York University law student who three years ago, while a student at Spelman College, organized a protest against Nelly for his negative images of black women. 

If our society is going to preserve a social norm against expressing negative racial or gender stereotypes, it just can’t be: 

White male Republicans are presumed racists, and must never say anything remotely similar.  Presumed Democrats, such as women, blacks, Jews, or those admired by a liberal media, are presumed to be neither racist nor sexist, and so can usually say something similar if it is "appropriate" irony, social commentary, or artistic expression.

To be accepted, a social norm must seem neutral to major social divisions, and to be reliably applied, it must be simple enough for most people to see clearly when it is violated.  The norm above is neither.  Hopefully we can evolve something better.