Aside from aging feminists like Gloria Steinem I don't think anyone is actually rooting for Hillary on the left. It is more the case of bad choice vs. 'what is this, I don't even...' that gets people to line up behind Hillary. I keep saying that Trump must be a plant, as any other candidate in the lineup, even Cruz, would have resulted in an automatic loss for her.
Personally, I am going to vote for Gary Johnson, because I don't have enough moral flexibility to perform mental gymnastics that would allow me to do anything else. It is that, or write-in Darth Vader.