How, they never say.
Yes, they do say. You just haven't bothered to see it.
Me, I don't want either Obama or Romney to win, as they are both extreme statists guaranteed to increase government tyranny. My third party vote will be entirely neutral -- I'll be leaving whether it's Obama or Romney up to those willing to endorse one brand of statism over the other. Instead, my third party vote is a vote FOR a plurality. If I "win," the next president will enter office opposed by more than half of the electorate, a situation which, if it follows historical precedent, will advance the cause of conservatism.