For example, just yesterday there was a thread talking about the US turning root DNS over to the UN. This thread turned into a jingoistic nightmare talking about how awesome America is, how they're the only true bastion of freedom, and how the rest of the world is a savage freedom hating backwater. That thread desperately needed more counter-balance, but no doubt people like myself were concerned that the groupthink became so focused that counter-balance would have been met with swift and numerous down downvotes (and risk site privileges because of being downvoted too heavily).
This isn't a complaint about downvotes, this is pointing out that downvotes change posting behaviour both for good (i.e. stopping people being jerks) and for bad (i.e. stopping opinion counter to the "group think").
There's no escalation. There's no feeding trolling behavior. There's no toehold on my future: I won't be curious about replies. It's cathartic. One click and I'm done expressing disagreement.
All of that still applies, though I am more likely to delete something I wrote these days and hopefully less likely to be an asshat because I try to avoid being one.
Anyway, sometimes I downvote in disagreement. It is often a better alternative to writing the nonconstructive thing I'd otherwise be inclined to write because what I'm inclined to write is the sort of comment I don't want to read on Hacker News. It's not the sort of comment I usually want to write either.
That sort of comment I don't want to read includes the sort of comment that provides a lot of entertainment elsewhere on the internet...we've all seen it: clever insulting outrage [feigned and real] written to win.
Anyway:
1. the guidelines suggest not commenting about being downvoted.
2. Questions about the site can be directed to the moderators via the contact link.
3. Good luck.