The Clintons have been here before, you see. They're being impeached all over again.
A must read from Michael Crowley in the New Republic that likens the bunker mentality in the dying days of the Clinton 44 campaign to... the impeachment battle of a decade ago. "Impeachment taught them that the specter of defeat could endear them to the public." So the worse it gets, the more they and their supporters dig in their heels.
They believe that Barack Obama, like the '90s-era House Republicans, has abused the system. They fume that he ran up his delegate lead in low- population red-state caucuses like Nebraska, Idaho, and Kansas with the help of activists who don't represent average Democratic voters. After losing Iowa, Hillary complained that its caucuses weren't accessible to night-shift workers and military personnel.
Actually, she was saying that even before the caucuses convened. Crowley continues:
Beyond those particulars, however, one gets the overall impression that the Clintons feel Obama shouldn't be here in the first place--that this "young man's" very claim to power is itself questionable. In this sense, the Clintons may be victims of their own sense of victimhood. The vileness of the Clintons' past enemies seems to have convinced them that their enemies always are, by definition, in the wrong. And that Obama's candidacy is almost like another illegitimate attempt to steal a White House that, in some sense, belongs to them.
Another point, from a Kos diary I can't find. To paraphrase: the core Hillary constituency of 50something 60something women look at Hillary and her family vs. career choices and see themselves, while they don't see themselves in Obama. Therefore, since the nomination fight is internalized and personalized, the intensity.