Whether personal or no, submarining comments simply because people disagree with them has always struck me as an intellectually awful "feature". I mean, think about that. People are actively encouraged to effectively censor comments simply because they disagree. What else can that do but encourage a pernicious group-think?
In fact, we should be doing the opposite: if it's stimulating discussion we want, then people should be encouraged to upvote well-made points, even if they don't agree with them.
And, if there's a downvote at all, then it should be for poorly constructed arguments that don't contribute to the quality of the discussion.
Edit: Looks like the two of us have discussed this before :)
https://news.ycombinator.com/item?id=12974834
And both times I've appreciated the civil discussion. Thanks for that!