This felt a bit too much like naive purity ethics back in 2008, and it looks even worse in the light of the current situation in the USA.
As for a substantive criticism:
Consider these two clever-sounding game-theoretical arguments side by side:
You should vote for the less evil of the top mainstream candidates, because your vote is unlikely to make a critical difference if you vote for a candidate that most people don’t vote for.
You should stay home, because your vote is unlikely to make a critical difference.
It’s hard to see who should accept argument #1 but refuse to accept argument #2.
The reason this is wrong is that your vote non-negligibly changes the probability of each candidate winning if the election is close, but not otherwise. In particular, if the candidates are within the margin of error (that is, the confidence interval of their margin of victory includes zero), then an additional vote for one candidate has about a 1/2N chance of breaking a tie, where N is the width of the confidence interval*. So as I explained in that link, you should vote if you’d bother voting between those two candidates under a system where the winner was chosen by selecting a single ballot at random.
But if they’re very much not within a margin of error, then an additional vote does have an exponentially small effect on the candidate’s chances. That is the difference between #1 and #2.
*If this seems counterintuitive, consider that adding N votes to either candidate would probably assure their victory, so the average chance of swinging the election is nearly 1/2N if you add a random number between 0 and N to one side or the other.
This felt a bit too much like naive purity ethics back in 2008, and it looks even worse in the light of the current situation in the USA.
As for a substantive criticism:
The reason this is wrong is that your vote non-negligibly changes the probability of each candidate winning if the election is close, but not otherwise. In particular, if the candidates are within the margin of error (that is, the confidence interval of their margin of victory includes zero), then an additional vote for one candidate has about a 1/2N chance of breaking a tie, where N is the width of the confidence interval*. So as I explained in that link, you should vote if you’d bother voting between those two candidates under a system where the winner was chosen by selecting a single ballot at random.
But if they’re very much not within a margin of error, then an additional vote does have an exponentially small effect on the candidate’s chances. That is the difference between #1 and #2.
*If this seems counterintuitive, consider that adding N votes to either candidate would probably assure their victory, so the average chance of swinging the election is nearly 1/2N if you add a random number between 0 and N to one side or the other.