> On HN, if a comment is well-written and appears to be made in good faith but is (in my opinion) wrong, I neither upvote nor downvote, I reply.

And this is evil being done as good men stay silent.

There might indeed be many that are not so petulant that they would downvote an otherwise non rule-breaking comment they disagree with, but few of them will find themselves upvoting something they disagree with either, and there will still be some that downvote it.

Thus, an unpopular opinion that otherwise contributes will eventually be downvoted for not receiving enough upvotes.