For completeness, here's the primary moderator 'dang' very explicitly confirming that downvoting for disagreement is still allowed at least as of 2 years ago:

dang: Downvoting for disagreement has always been ok on HN.

https://news.ycombinator.com/item?id=17666145

That's an awful policy.

I don't care about the imaginary internet points, but it doesn't take many downvotes to bury/kill/whatever a post. If a few early responders "downvote disagree" then nobody will ever see it.

It's almost as if they thought, "How can we best encourage groupthink?" and this was the answer.

And yet, years after Dan took over as moderator, and over a decade after Paul posted his comment, the site is still going strong, and arguably is one of the best places for discussion on the internet. There is clearly a tension between allowing people to "bury" unfavorable opinions and denying them the ability to express themselves at all, but somehow it mostly works.

One thing I'd recommend, if you haven't done so already, is to at least occasionally browse with "Showdead" turned on (accessible through your profile link in the upper right). The majority of the things that are dead deserve to be, but the others can often be rescued by vouching for them.

It also may help if you think of voting as "rearranging the page" rather than killing an opinion. The opinions are still there for those who wish to upvote them, they are just at the bottom. Like the dead comments, most of the things greyed out at the bottom deserve to be there---but the rest one can try to rescue with an upvote.

    And yet, years after Dan took over as moderator, 
    and over a decade after Paul posted his comment, 
    the site is still going strong, and arguably is 
    one of the best places for discussion on the internet. 

HN is a success and does the vast majority of things well. But it makes no sense to sweep aside criticism with "well, it's working." It succeeds because of the things it does well and in spite of the things it does suboptimally.

HN moderation generally works well in spite of the actual technical implementation; it succeeds because HN has a high-quality readership who generally follows the internet etiquette of "downvote posts that harm the discussion, not simply because you disagree."

    One thing I'd recommend, if you haven't done so already, 
    is to at least occasionally browse with "Showdead" turned on 
    (accessible through your profile link in the upper right). 
    The majority of the things that are dead deserve to be, 
    but the others can often be rescued by vouching for them.
 

Amen! I wholeheartedly agree and I do that for this very reason.