When you choose evil without coercion, even if it is a lesser evil, there's something seriously WRONG there.
-Renegade
Not.. necessarily. Take a US election, with two candidates, and other marginalized ones. You can vote for the one that would do the least harm. Or you can vote for someone else. Or you can not vote at all.
Not voting at all is not making a choice. Similarly, if pragmatically your candidate won't win... that's not really a choice either. Those kinds of choices for the non-mainstream candidate are made before an election and during the campaign. Not at the ballots. Once it becomes obvious that the marginalized candidate won't win, all you do by voting for them is reduce the pool of effective votes.
Voting for the lesser evil in that case, is the pragmatic choice. You're not actually choosing the lesser evil- you're choosing against the greater one.