I remember the pundits being perplexed. In speech after speech he touted himself as the one who could rein in the out of control Democratic liberals. He pretty much ignored Bush that election.
His supporters seemed to have fallen in love with that strategy. He essentially built up his own party-in-a-party. The only good Democrat was a Clinton or a supporter of a Clinton. This site http://www.hillaryis44.org/ is apropos.
I used to be a fan of http://www.bartcop.com. But it became clear after awhile that he also suffered from this issue. In 2004, with no Clinton even on the ballot, I went through two weeks of his posts and tallied up his - the ones he authored, not stuff he linked to - attacks on Republicans, criticisms of Democrats (mostly Kerry) or support of Democrats. The ratio was something like 5 attacks R to 10 critiques D to 1 support D.
There are still a lot of Conservative Democrats out there who elect Conservative Democrats locally while voting for the Republican Presidential candidate. They might vote for Hillary in the GE, but nobody else.
In addition, I knew several lifelong Democrats who left the Party because we elected a Black President. They were all for giving Blacks a fair shake and a helping hand up. But putting one in charge was going too far. "My God, people, do you realize what we're about to do," was the shocked phrase I heard often in 2008. They were quite surprised to find that most of us were perfectly happy with this. The thing about a bigotry is that a person assumes mostly everyone else feels the same way since to them it feels normal.