Due to non-linear effects of propaganda, a single/small-group of people working in a concerted manner can easily change group dynamics specifically its "fairness perception" and thus ultimately lead to the detriment of the group itself.
But ultimately a site moderated by up and downvotes that wants to keep a relatively light hand on moderation is going to end up like what HN is today. Changing the voting structure on the site or the moderation POV on the site would be a radical change and could change the entire site's culture drastically.
The stock answer to the above charge is that "this is more of the individual's perception and not reality" and "HN is just representative of what is going on in the society". Also;
Ask HN: What is Hacker News's business model? - https://news.ycombinator.com/item?id=23671531
Humans will game everything they can to gain an advantage even if it were only for silly imaginary things like "upvotes". Add in our psychological propensity for "Tribalism" and you can see we have to be a bit paranoid when it comes to social networks. Introduce anonymity into the game and things get even more worse.
So it behooves the HN owners/mods to have some sort of system to analyze everything and do some inferences for insight even if they don't act on it immediately.
Some users have already developed some models and shared it on HN; eg:
1) Show HN: Exploring HN by mapping and analyzing 40M posts and comments for fun - https://news.ycombinator.com/item?id=40307519
2) Mapping Hacker News to find who knows what in the HN community - https://news.ycombinator.com/item?id=41069527
3) Show HN: Hacker Atlas - A map of what Hacker News talks about - https://news.ycombinator.com/item?id=49844497
4) Hacker News Data Map - https://news.ycombinator.com/item?id=42035981
PS: There are a bunch of books on "Social Network Analysis" which one can consult. A good one is the book of the same name by Tanmoy Chakraborty.