In the seven years I've been on HN, it has gone through different phases, each with a noticeable change in the quality of the comments.
One big shift came at the beginning of COVID, when everyone went work-from home. Another came when Elon Musk bought X. There have been one or two other events I've noticed, but those are the ones I can recall now. For a short while, many of the comments were from low-grade Russian and Chinese trolls, but almost all of those are long gone. I don't know if it was a technical change at HN, or a strategy change externally.
I don't know if it's internal or external or just fed by internet trends, but while it is resistant, HN is certainly not immune from the ills affecting the rest of the internet.
HN has mechanisms to detect upvotes and comments that seem to be promoting a product or coordinated in some other way. I'm not sure what they do behind the scenes or how effective it is but it's something. Also other readers downvote bot spam. Obvious bot/LLM-generated comments seem to be "dead" quite often, as are posts that are clearly just content/ad farm links or product promotions or way off-topic.
How are you so sure these users are actually bots? Just because someone disagrees with you about Russia or China doesn't mean that's evidence of a bot, no matter how stupid their opinion is.
16 year HN vet here.
This place has both changed a _lot_ and also very little, depending on which axis you want to analyze. One thing that has been pretty consistent, however, is the rather minimal amount of trolls/bots. There are some surges from time to time, but they really don't last that long.