That’s a nice platitude, but there are only two outcomes, no matter how much you might wish there was a third. Your options are to help, abstain, or hurt. Abstaining means you’d rather not help, so again, in my mind, you’re a moron.
Third party candidates are only viable when one of the major parties collapses, and the major parties only collapse when they consistently lose. So, if you actually want a viable third party, you should vote for the major party you dislike the least. Otherwise, you’re just perpetuating both.