Well. We're going to be all grown up here and refrain from a profanity laden rant about the short sightedness, stupidity, probable monolineal heritage, selfishness and arrogance of those who proudly either voted Libertarian because "Romney is insufficiently pure" or "Vote your heart not you head."
Besides, Stingray does it far better.
Let us, however, walk it through.
1) In politics you never get what you want - at best you get a series of increasingly less offensive compromises, and often you only get compromises of a similar level of foulness if not downright losses.
2) When voting and the choices are Evil, Less Evil, and On A Cold Day In Hell - the SMART person who actually CARES about consequences votes for Less Evil and tries for a better choice in the next round. This, of course, requires work as opposed to standing around whinging and posing nobly about how you are going to vote for Cold Day In Hell.
3) When you vote for Cold Day in Hell because Less Evil (or their brother, Evil Restrained By Thought of The Next Election) is insufficiently pure, you effectively vote (by taking your vote away from a viable candidate) for Evil (the unadulterated and unrestrained version).
When Unadulterated Evil wins and has no restraint (like, say, a need to worry about ever being elected again) the odds of dramatically bad things happening go from "so-so" under Lesser Evil to "Katie Bar The Door" under Unadulterated Evil with a taste for signing Executive Orders and ignoring little things like federal law and Constitutions.
While pointing all this out may be futile, I will continue to hope that you will discover a cure for your regrettably severe case of cranio-rectal infarction. In the meantime, those of us with more than a single branch on our genetic map will be busy about trying to do damage control after the howling cluster you and your progressive friends gave us on Election Day 2012.