If you’re in the US, with a two party system, not voting for the less evil is actively enabling the greater evil.
You think Trump or any GOP candidate wouldn’t do the same? Or worse? They’re certainly not going to do anything better than Biden.
Voting on principles is for the Primaries. Try and get the best candidate possible that you actively believe in into the race. Election Day however is when it’s time to put your adult pants on, accept the world is messy, and vote for the least worse option possible, because otherwise you’re just abetting the worst option.
You have roughly equal amounts of people pulling the lever in the “kill one person” direction and the “kill many people” direction.
The only people interested in pulling a lever that adds a third rail are the “kill one person” crowd. The moment enough of them let go, the lever goes in the “kill many people” direction because that crowd has no interest in a third rail, they quite like the “kill many people” option. You’ll never get enough people to join the third option from both crowds simultaneously. No third party has seen any real form of success in nearly 200 years within the current system. Changing the system is necessary but taking out hands off the lever is a disaster.