Is negative reputation abused on HN?

HN seems to be plunging into a downward spiral where any posts that another disagrees with gets down voted - regardless of the severity of it's language.

I can understand the point of issuing negative reputation for spam or abusing comments, but I've seen innocent opinions down voted into oblivion simply because it's unpopular. This creates a negative atmosphere for discussion - after all, who would want to risk putting their opinions HN if they're only going to be subject to "hit and run" down voting. And the fact that the members who do down vote but don't express why is doubly disappointing because they're not even "brave" enough to risk expressing their own view points.

Then you have comments that are sometimes wrong (not arrogant, just inaccurate). While I can sympathise with wanting to push incorrect comments from view, it too creates a negative atmosphere when simply replying with a polite correction would work better. "Better" because the person who made the falsehood learns something new; better because other readers who believed the same falsehood also learns from the mistake; and better because you're not discouraging individuals from leaving comments just in case someone down votes them.

I've noticed that this trend of down voting comments has been on the increase in recent months - which I suspect is down to more members crossing the karma threshold required to gain access to the down-vote button. And with that, many more people with different views and experience are in a position to mark posts down just because of a differing opinion. Thus I wonder if it's time to review the system. One idea I propose is where comments down voted are visibly marked as [spam] or [abusive], thus making it very clear when there's been abuse of the peer moderation system and discouraging members from issuing negative reputation based on differing opinions.

While I'm sure there are a great many people who are happy with the status quo, I do think the way comments are so frequently and -in my opinion at least- unfairly down-voted does create a negative environment to communicate in. Which is a create shame as I used to consider HN one of the most friendly and open communities to discuss various topics.