It's one thing to downvote something that's factually incorrect, mean-spirited, ect. But downvoting a post that expresses a well-formed, but subjective opinion? I used to just ignore opinions that I disagreed with; and only downvote flames and things that were factually incorrect.
That, IMO, is how I interpret how the “Eternal September” plays out here: When people penalize opinions instead of facts and flames.