Yeah, I suspect that they're pretty aggravated by it. It does have the advantage of keeping her name in the news at a time when she might otherwise vanish, and "all publicity is good publicity", but I don't know how much her staff are enjoying those sour grapes.
It shouldn't have come as a complete surprise, though. She's always had high negatives, though it's disappointing that so many of them come from concerted Republican campaigns to smear her. (Remember that Barack Obama had a fightthesmears.com site set up the minute he won the nomination.) It's unsettling to have liberals repeating Republican talking points, in addition to creating their own.
It set her up for there to be some kind of opposition. And the Democratic party has been taking its liberal wing for granted for quite some time, allowing centrists like Obama and both Clintons to get their votes knowing that they'd be unable to get more than the palest pink liberal agenda items actually achieved. I happen to be a left-leaning centrist myself, and think that's about the right thing, but real leftists are understandably upset.
In the end they have the opportunity to realize that they've dragged one candidate a bit left, and get that candidate elected over a far-right candidate. That would be a win, and if it's not the win they were hoping for, it's also the one that doesn't have every Republican and half of the Democrats upset at going too far left. We'll see if they'd rather have half a loaf than none.