Because (from a recent MorOn.Org email) it makes Democrats say things like this:

I think she’s far too inexperienced to be in this position. I’m all for a woman in the White House, but not one who hasn’t done anything to deserve it. There are far many other women who have worked their way up and have much more experience that would have been better choices. This is a patronizing decision on John McCain’s part- and insulting to females everywhere that he would assume he’ll get our vote by putting “A Woman” in that position.–Jennifer M., Anchorage, AK

Let’s do some subtle re-writing so that you can see why this makes me giggle so:

I think he’s far too inexperienced to be in this position. I’m all for an African-American in the White House, but not one who hasn’t done anything to deserve it. There are far many other African-Americans who have worked their way up and have much more experience that would have been better choices. This is a patronizing decision on the Democratic Party’s part – and insulting to African-Americans everywhere that they would assume they’ll get our vote by putting “An African-American” in that position.

Look for Jennifer’s PKB (pot – kettle – black) argument in various forms everywhere.