I've encountered a bunch Bernie supporters who find Hilary disheartening enough they won't vote for her under most circumstances. And they aren't confined to reddit. Maybe this will depress you, maybe it will give you some understanding, maybe it will just reaffirm your opinion that we're all delusional. But my personal experience as a life long Democrat, in my 30s, living in a swing state, is that I haven't spoken to anyone willing to vote for Clinton if she gets the nomination except my mom. Even friend's parents who have been democrats for 30+ years are saying they won't vote for Clinton if she gets the nomination.
The two responses I have heard are 1) Going to vote trump because maybe America needs to see some awful for 4 years to have a chance to right ship on to a more progressive path rather than letting the whole thing drift slightly to the right in corporate empowered mediocrity for 8 years and beyond. 2) Not going to vote, because fuck the whole thing. I hate trump but I also hate Hilary, and I don't want to vote for someone I hate.
I fall in the latter (although perhaps if cruise gets the nomination I may have to vote for her because I don't just hate him I fear him). But if it's trump versus Hillary, I will be sitting out my first election since turning 18. I was raised democrat, and raised to believe it is important to vote, but I've grow more and more apathetic about politics over the last 15 years. You pair that growing apathy with a visceral dislike of Hilary that I can remember feeling even during childhood in the Bill years, and my attitude is fuck it.
That's the thing Hillary supporters are ignoring. Beyond her policy, she draws a serious level of dislike from a not small amount of democrats. A lot of it relates to things she's done and policy choices, but a lot of it is just really about that gut feeling she evokes for people. You can say that's not what politics should be about, but we are people. And we aren't getting to vote on issues, we are voting for the candidates, so of course likability (or un-likability) matters. I like Bernie. My dad is from Vermont and I've followed Bernie a bit for years, but I'm hardly the Bernie or nothing type. I'd like any actual progressive candidate like Elisabeth Warren, but I would still unenthusiastically vote for Gore or Biden because they would be clearly better than the alternative and I was raised to believe it was a duty. But Clinton... I just can't do it.