As I remember someone else pointing out, downvoting when disagreeing greatly jeopardizes HN's quality. As you pointed out, people should be encouraged to upvote

As I remember someone else pointing out, downvoting when disagreeing greatly jeopardizes HN's quality. As you pointed out, people should be encouraged to upvote opinions of high quality and downvote opinions of low quality. If people choose to go against this and up/downvote due to how their views compare with the commenter's views, HN will quickly be filled with posts that go with the majority opinion. Not only will these posts get the most exposure, people will stop posting their views when they are in the minority. Obviously you can see the damage that this would create.