One problem with the "downvote only offensive/unconstructive/troll-type posts" theory of down-voting becomes apparent when you have a highly upvoted but factual

One problem with the "downvote only offensive/unconstructive/troll-type posts" theory of down-voting becomes apparent when you have a highly upvoted but factually incorrect post, with a factually correct counterpoint that hasn't received any attention in response. I think it makes sense to both upvote the (correct) response and downvote the overly-upvoted mistaken post; this brings the point-balance of the conversation back in line with reality, rather than letting incorrect posts which might attract a lot of upvotes because they pander to a particular sentiment, or repeat a common myth, dominate the conversation.