Yuu voted for Romney; whether or not you intended it, you voted FOR turning the Republican party hard left. You may have perceived it as voting "against" Obama, but that was a false perception; you ONLY voted FOR turning the Republican party hard left; there was no place on the ballot for you to vote "against."
I voted for Tom Hoefling though I knew full well he wouldn't win. I voted FOR reducing the popular mandate of whatever leftist won, Obama or Romney. I voted FOR keeping the Republican party to the right, I voted FOR rejecting leftism.
You voted FOR embracing tyranny in the Republican party. You intended to be voting for something else, more likely you intended to vote "against" Obama. But when the rubber hit the road, the only thing you voted for was to move the Republican party and the USA hard left.
I stand by what I said. If you stayed home or did a write-in, you helped put the Marxist/Muslim in office.