Here's another hypothetical for you. Two people are given $100 to split, one person makes the offer on how to split it, and the other chooses to accept or decline. If they decline, nobody gets anything.
Rationally, the way this plays out is that the first person offers a $99-$1 split, and the other person accepts, because $1>$0. But when researchers have actually run this experiment, they've found that people tend to reject offers below $30-$40, and people tend to make offers accounting for that. Somehow, the "irrational" behavior results in a more optimal outcome.
Once upon a time, in the New Deal era, Democrats offered something closer to $30-$40. But somewhere along the line, people started employing this "lesser evil" nonsense, and the offers got worse and worse. Now, we're past the point where they even offer us $1. Now they offer us "We'll still commit genocide, but slightly less."
I'm completely baffled by how anyone can still be committed to this clearly failed and irrational strategy of "lesser evilism." Even if you personally think it's the right move, surely you must at least understand that this isn't how other people are going to behave.