With the amount you see people say 'I'll get downvoted for this but...' then go on to be the top post, I think the downvoted helps more than hurts.
There's groupthink of course, but I feel the HN community is more responsible with it, and that comes from someone who often disagrees with the majority (personally, rarely expressed).
Investors, customers, and peers read HN, so maintaining a clean history can seem moderately important.
I'm curious if you think there's a problem, and why. Maybe I'm just inside the bubble.
On controversial topics, I see lots of better comments downvoted for a while when they are new, but they tend to recover within a few hours.
It's an imperfect system, but I'd guess it is a net positive at least most of the time. It does help to filter out when people are just being total jerks.
I generally try to upvote only. It really annoys me to see some comment down voted to grey oblivion with no follow-up comments explaining why. Particularly when looking back at older topics; was the post wrong, or just unpopular?
One thing you can try is looking through your comment history and see which of your comments got the most upvotes. One of my highest upvotes was in a thread about whether software engineers should waste time doing telephone customer support, and I linked to a story of when William from Microsoft took a customer support call:
https://news.ycombinator.com/item?id=15813387
Another was a comment about where I got my first customers:
https://news.ycombinator.com/item?id=14192711
Or linking to a strategy for finding product ideas:
https://news.ycombinator.com/item?id=14040708
Checking your most upvoted comments can also be a way to find topics that you should turn into a blog post. If the HN community found it interesting and suddenly gave you 10x the upvotes you usually get, then it's probably also useful to the wider world.
When I've been downvoted, it's usually because I've poorly researched something & provided incorrect information.
I personally think the downvoting feature is fine, just really overused by people with much more karma that it makes the website less enjoyable to visit, especially for new people. And sure, one of the things I love about this site is that there are legitimate gurus on here, but a lot of people take their ability to downvote to classic Dunning Kruger syndrome.
Perhaps a quarter point penalty for downvoting to stop spamming and for people to consider the worthiness of a downvote or ignore. After all, Karma is how you treat others, and constantly negging them with no explanation isn't very kind at all especially for the majority of the people on this site that just want to learn.