Campaigns are emotional things, not only for the candidates, but also for their supporters. When you invest time and/or money in supporting a candidate, and that candidate loses, it hurts. When the candidate is running for the presidency, a vote that political commentator Mark Shields once called "the most emotional vote in American politics", it hurts more. So it is understandable that Clinton's supporters are not happy with what seems to be her probable defeat for the Democratic nomination.
The bitter feelings were probably inevitable when the two front-runners for the Democratic nomination became Obama and Clinton. African-American voters have been, since 1964, the most reliable demographic group of voters in the Democratic coalition. They vote usually around 90% for the Democratic presidential nominee.
White women are the next most reliable group in the coalition. A lot of party activists are women. They do the work that makes the party competitive in a lot of races.
An Obama/Clinton confrontation meant that the historic opportunity for one of these groups to elect a president was going to be lost. Further, it could mean the loss of an opportunity that won't come again for a long, long time. Right now it is hard to imagine either an African-American candidate or a woman candidate for the presidential nomination that will have the opportunities that Obama and Clinton had this year.
Given all of that, it is understandable that Clinton's supporters are looking for an explanation for her possible loss. A lot of them blame sexism, especially from the media and also from the Democratic Party's leadership.
There is no doubt that in many cases Hillary Clinton has been treated in a condescending and sexist manner by the national media. There is also no doubt that Obama, like Clinton, has made comments that were inappropriate and unfortunate. Those two things don't mean, however, that Obama wins are only about sexism.
Here's what's not sexist. It wasn't sexism that made Hillary Clinton vote for the Iraq War Resolution in 2002. It wasn't sexism that made her campaign ignore the states that have caucuses instead of primaries. It wasn't sexism that allowed Obama's campaign to do a better job of mastering the rules of the Democratic Party, as this article points out. It wasn't sexism that caused her to allow Mark Penn to establish control of her message until it was almost too late. It wasn't sexism that made her make remarks about her appeal to "hard-working Americans, white Americans", comments that seemed to suggest that only "white Americans" are hard working. It wasn't sexism that made her talk about being under sniper fire in Bosnia or about the RFK assassination. It wasn't sexism that caused hundred of thousands of Obama's supporters to make small donations to help fund his candidacy.
The fact of the matter is that Obama ran a much better campaign than Clinton, which is why he has won more delegates than Clinton. She started out with more money, more support among elected Democrats and among Democratic Party leaders, better name recognition, and the advantage of having been through two national campaigns, plus a campaign in a very populous state. She also had a very dedicated group of volunteers supporting her. Even with all those advantages, however, she couldn't close the deal with Democratic primary voters. The cause of that failure lies more with her decisions than with sexism in the media or in politics.