I'm gonna point out one single thing that certain people keep missing. It is not the job of the people to vote for the politician, it is the job of the politician to convince the people to support him. When I say support I mean give them some reason to vote for the person, not against some evil on the other side, especially if the politician in question is practically as evil.
People have policy positions, and should support politicians that hold similar positions as them. If you do not believe in the positions I believe in, I will not vote for you and many others are like that. I also have to believe that you're not blowing hot air (obama) and truly believe the things you say and would fight for them. Biden isn't offering anything to the left yet he's demanding the votes. You can point out the terrible offers he's giving to the left that aren't gonna do anything, as him offering something but then I would simply point out to you that I also don't believe him cause he has a 40 year history of punching left.
You can't voter shame people like that and you can't go off about how bad Trump is to people like that and in fact, that's how people in this country and the rest of the world should be. We should have positions that we hold dear, and if our politicians don't support these positions we don't support them until they do.
I pointed this out to certain people numerous times, you'd vote for the nominee regardless of who it is, I'd only vote for the nominee if they supported the positions I believe in and I trusted them to do so. Only 2 people on that stage I trusted to that degree and only 1 had the support to pull off a possible win against the system that's designed to crush people like him. In the end he was crushed and with that I have 0 reasons to vote for either of the 2 main parties in november. Moving on policy is very important, but trust is more important and Biden can never win that from the left.
Let me explain segments of the real left to you. There are progressive leftist, this is the group that would probably go for Biden after Sanders to stop Trump. Honestly, they buy into the lesser of 2 evils but they're not motivated and might even just not vote. There's the populist Left, these people aren't gonna vote for Biden they oppose him. They'll vote for policies and Biden can possibly win them over by moving policy but its hard cause they still wouldn't trust him.
The Hard left, These are the true uncompromising people you think that I am but I'm more populist than anything else. These are the ones who would find things like you believing in russia gate and immediately throw away support for you. They comb through every word you said to see if you were using some CIA talking point before considering you. They'd vet you so hard that its not funny, but you want to know something about the hard left? They may not support you in the primary because you don't align with them but in the general if you're somehow like a Bernie or a Tulsi, they would possibly take a chance on you and push you over the edge.
The Progressive left are the ones who were fooled by Warren for the most part, The Populist left are the ones who voted on Policy and Trust and were 100% Sanders the entire time while also cursing him out whenever he'd give into things that the hard left pretty much came out and said screw you bernie for. There's another group which is derived from all 3 which is the angry left and well, they are more likely to vote Trump just to say screw you to the dems. Either way, you can't voter shame these people because they would laugh you out of the room and people see how disgusting Biden supporters have been to those who don't want to vote and have been turned off of how toxic his supporters are. But hey its not my problem.
tl:dr Biden has the blue no matter who crowd and the tiny never trump republican crowd. If Bernie was the nominee, he'd have the progressive left, Populist left and some of the hard left + vote blue no matter who crowd. But again its not my problem. If you want Biden to win, go phone bank and text for him do the work and put in the time cause you're not gonna win people over by saying Trump bad. We Know, and Biden aint much better so good luck.