Here's the relevant part of the answer:
"I get it: you disagree with the call the moderators made on that one. You know what? That's gonna happen sometimes. It even happens to me. I think it might be time to move on. There are 50 million+ posts on this site, deciding where to draw the line is not an exact science. It would be impossible to be completely consistent if only one person were making the decision on every post, but there are so many differing factors, from the tone and substance of the post itself, to the content of the alerts, to who happens to moderating that day, to how busy we are. You name it. We try the best we can, and I'm sorry to say that is the best anyone here is going to get as long as we are on DU2."
http://www.democraticunderground.com/discuss/duboard.php?az=show_mesg&forum=437&topic_id=4678&mesg_id=4703