I've seen intelligent and insightful HN posts down voted simply because they went against the status-quo. If this is allowed to go on, people will be afraid of making controversial (but intelligent) posts, and this place will become another reddit.
This is insidious because it encourages people to be the first to say the least interesting thing in order to get rewarded with comment karma. Those comments bubble up to the top of the thread, where they're held aloft by more and more people who see their existing opinions restated.
Ultimately the reward structure encourages discussions where people are indulged, in the same way the punishment structure discourages people being challenged.
I'd say this effect is more pronounced on Reddit than HN, but you can see it here too.
I'm not looking for "edgy" comments, I'm just saying that it's more useful in the long run to upvote comments that provide new information or perspectives, or at least state a common sense position in a different, compelling way.
Partly this is a first-poster thing. If you post early, then you'll either get a lot of up or down votes. Take time to post, and well, might get nothing.
It would be interesting to see if time-weighting the votes somehow could improve the signal. Maybe give less weight to someone who rapid-fire downvotes comments faster than they could possibly read them?
Perversely, downvotes aren't available on comments older than 24 hours, but upvotes are, so comments that attract a mixture of up- and down-votes get a strong upward bias on votes they attract after a day (since the upvotes happen and the downvotes don't).
Not sure how relevant that effect is to more short-term issues, though.
Flagging operates similarly; as there is no reason attached to the flag it is simply 'dislike'. Slashdot's tags were much more nuanced.
Oh certainly, it's just that this seems eqally applicable to upvotes, hence why the asymmetry seems perverse.
The best thing to do here is for the community to step in and actively up-vote unfairly downvoted comments.
Every tool will be abused sometimes.
I think the voting system mostly works extremely well - the system needs to be viewed as a whole with all the compromises that includes, rather than drill down on one particular failure.
Sometimes people use voting for bad reasons — I know I have (though I am quite conscientious to try and learn to vote more carefully).
It is not possible to download posts on HackerNews, no matter how many karma you have. Did you mean comments? Because I think that actually one of the strongests points of HN that all posts will get equal footing. (they can be flagged though)