@JonKramer
Good question. Perhaps it's because, in the short term, you're choosing to have no impact on the outcome of that particular election, or even to make it slightly more likely (by half a vote) that the greater of two evils wins.
The counterargument is that, in the longer term, if enough people do this, and if the less evil party knows they are doing it, then the less evil party will tend to look for candidates that are actually acceptable, rather than just not quite as evil, and that would be a very large benefit.
I can imagine counterarguments to that. The less evil party may not in fact realize that that is why they are losing elections, for instance, and think that they have to be even more evil to win. (The Democratic Party seems very prone to this line of thought!) Or that the short term danger of the greater evil is large enough to make the longer term benefit moot.
But people should at least be able to understand your argument! This issue seems to polarize people to an odd degree; I don't really know why...
@JonKramer
We as a species aren't great on objective reality. :)
(Whether the concept is actually coherent is another whole question; we as a species aren't great on any variant of the idea.)
Nor on dissent. :)
But we muddle onward...
@ceoln It always seems to be a blind loyalty to how the voter imagines their chosen one to be, and not often based on objective reality. Or how evil the opponent is, also not often based on objective reality. They can't handle any dissent. Or any voices that don't agree to them without reservations.