I think voters wanted somebody to the left of Obama, and Hillary felt like a big step back to the '90s.
Here's a fact that makes my leftist friends mad at me(since 2008) ... Hilary IS and was left of Obama. People saw what they wanted to see in Obama because he is so charismatic. A lot of people hated Hilary because of the constant dragging of Hilary in the media for over 20 years.
I fell for the anti Hilary propaganda. And it wasn't until she was a serious contender that I started looking deeply into her record. She's actually pretty amazing. If I ever meet her I will definitely apologize for falling for the bullshit.