I agree that it's become a flame war, and IMO part of the issue is that at times people promote (up/down) vote based on agreement, and at other times people vote based on promoting a good conversation.
I really want to see two voting mechanisms, an I agree woot, and another button that indicates is a well constructed argument that I think deserves conversation and views because it will promote healthy conversation. I'm not convinced people would use these appropriately, maybe they sit behind a "vote" count or you only get 5 votes a day or something, IDK.
We've gamified agreement on these platforms, and I see things swing based on who shows up. I've seen my votes swing wildly based on what I'm interpreting as someone of a particular ideology come through.
Either way we need to gamify conversation and not agreement, I don't know how to do that, but I think HN would be a great place to experiment with that idea.