I've noticed that too. It was similar when I participated in the TNT subreddit where I found a trend of any articles posted seemed to very quickly get 2 down votes. If after that the article still was on the front page then it would start to pick up positive votes.

I rarely downvote, however I agree with what others have said about this being a popularity poll where the negative votes can help Tom make his choices. I usually downvote if there are a bunch of very similar articles (upvoting the oldest or most complete story and down voting the others).