Many times people down vote because of the content of the message.
Example: Let's say someone posted a video of Glenn Beck flipping to an anti-gun stance. People would be outraged! They'd most likely down vote the thread in disgust. In this instance it would have nothing to do with the poster or his reason for posting the thread, but the fact that Glenn would have made the wrong decision (again).
^That's a hypothetical, he never said that.