That is literally not how it works. That’s how people think it should work, but when you see that it doesn’t, you have to turn back and review your premises and your model. I know the way you think it should work and how you want it to work, but when it doesn’t work you need to revise.
The problem is this - the feedback loop is insufficient and the correlation is unclear. If you are directly negotiating with someone, then you can play Ultimatum. If you are one of a hundred million people casting a vote for one person or another, you cannot. Perot cost Bush I the election, and Nader cost Kerry the election. Neither party decided that they needed to move in the direction of the spoiler candidate. They’re especially not going to do so for 3p candidates who pull in the low single digits, even if they lose by low single digits, because they’ll think they can get more by moving towards the center.
You can vote however you want, but don’t base it on a theoretical foundation that has less than zero application to the scenario you’re modeling. It really, honestly is a minimax choice, and if you are truly an ally for those of us in marginalized communities, you have to recognize it.
I’m not being a right winger here - I’m a member of the DSA and this is in line with what they (and people like Chomsky) advise. But I’m not talking about even that angle. I’m just talking minimax and BATNA. If negotiations fail (ie we didn’t get Bernie), the best alternative is Hillary. At least Roe wouldn’t have been overturned and we wouldn’t have states suing to make ten year olds give birth to their rapist’s babies.