Astroturfing and reputation management are a thing. Also, big companies have a large number of employees some of who hang out here and will simply take offense by association, which could be more than enough to explain the effect even if the company itself has nothing to do with it.
HN is no longer niche.
> Who has the budget for this?
Apple, Google, Microsoft, Amazon, Facebook, Twitter and whole pile more if they wanted to it would be a round off error on their budget but besides one of those I don't think there was ever hard evidence that this happens.
Reputation management is becoming more and more important to brands.
Every enterprise, basically.
You subscribe to social media monitoring as a service, they monitor the fire hose and flip on the bat signal as needed.
It’s dirt cheap, relative to not knowing what’s said about you.
Ummm, Google(/Alphabet)?
You might have heard of them? Fourth biggest company (by market cap) on the planet? They have budget to do all this shit: https://en.wikipedia.org/wiki/X_(company)
Pretty sure they wouldn't even notice the costs of downvoting every single negative comment about them on every single website they're already crawling and mining for keywords and sentiment...
No brand or PR team that I've ever been near has the capacity to monitor and then manually downvote this kind of thing, even on major sites, let alone a niche news site like HN. Who has the budget for this?