1. Lesser-evil voting guarantees that Democrats will continue their rightward drift, maintaining a destructive and oppressive status quo ("it's dangerous to continue thinking that we can continue the way we are")
2. If losing this election upended that status quo and forced a radical shift to the left among Democratic candidates (if it would "bring the revolution"), the long-term decrease in suffering would be worth the short-term increase in suffering.Setting aside Sarandon's rhetorical flourishes, it's worth noting that the #NeverHillary argument is really just a delayed gratification argument. It advocates a net reduction in destruction, suffering and oppression by putting an end to a Democratic status quo that, over the long-term, would be worse for everyone than a single Republican administration. This is the exact opposite of a "tolerance for human sacrifice", as Michelle Goldberg puts it in her critique of #NeverHillary voters. If Sarandon is right, it is in fact liberals like Goldberg who wants to exact a greater human cost over the long term.
Here, I just want to make the simple point that there's a demographic with a powerful, privileged incentive to reject this logic: olds.
Old people have no direct personal stake in long-term political outcomes. They have the luxury of only having to worry about what happens in the short term. They don't have to worry about what happens over the span of decades if you keep voting for increasingly right-wing Democrats, because most of them will either be dead or enjoying a comfortable retirement. They have almost nothing to gain by using their votes to discipline the Democrats into running better candidates, because that is a long-term political project that doesn't yield them immediate advantages.
When olds like Joan Walsh and Michael Tomasky lecture young people for worrying about their future, they are doing this from a position of absolute privilege. For them, a Hillary Clinton presidency is acceptable, because they get all of the advantages and none of the disadvantages. They get low energy prices that come from Clinton's middling climate-change incrementalism, and none of the droughts, rising oceans, and global instability that we'll see by the end of the century. They can tell young black people that their votes don't matter, because olds won't be around to see the devestation wrought to black communities by Clintonian economic governance; olds will, however, get the nice short-term bump in their 401(k) that comes when Hillary inflates the next bubble. They can tell young women that their fights for childcare and family leave are overhyped, because the boomers have already sent their last children to college.
Young people have no choice: they have to play the long game. Some of them may decide that the grim future which lesser-evil voter guarantees them just isn't acceptable. They might even conclude that it would be preferable to endure four years of a Republican administration if it means that Democrats nominate an acceptable candidate the next time around. This calculation is debatable, but it's absolutely ridiculous for olds that #NeverHillary voters are trying to increase oppression and suffering. That analysis only makes sense if you have the privilege that old people have: the privilege of not caring about the future.