I've noticed something like that recently, although I hesitate to call it a trend from just a few observations. I suspect some people upvote/downvote based on personal feelings alone, or whether they agree/disagree with a post. I prefer to be a little more disciplined with my voting. I like the way stackexchange et al works in this regard, where negative votes have a cost to the voter and voting is rate limited (everyone has a maximum number of votes per day), this ensures that most voting is taken seriously.