Better question for the "lesser of two evils" crowd: What's the endgame here? In my experience, the strategy is to try to hold together enough of a Democratic voting bloc by browbeating and berating leftists to keep the greater evil out of office, and the result is that politics has marched steadily to the right, Now we're teetering on the edge of fascism, with a Democratic President supporting genocide in another country and breaking strikes like he was ol' Ronnie. We can't go on like this. It can't work forever. Eventually, the threat of a fascist getting into office will be a reality; they only have to win once, and we have to win every time. It could very well be 2024 that they do it.
At what point do we attempt something better? As commentators like Thomas Pikkety have written, there are important issues that transcend the traditional left-right spectrum, that could peel away a lot of working-class voters who feel abandoned by the neo-liberal policies of the Democratic Party.
Do we just keep voting for the lesser evil in the hopes that we can do it long enough for some unforeseen, future political shift to just sort of happen before the lesser evil is also a fascist?