No doubt they do. What are our options? We can fantasize about this and project our fantasies onto other users—or we can look for some sort of evidence, any evidence, before making claims. If you want to believe in diabolical state actors manipulating the community and leaving no trace whatsoever, how could that ever be falsified? The only thing you have to go by in that case are your own assumptions and preconceptions.
On HN, we choose the other fork of that branch and look for evidence. I'm not saying the bar is high, but there needs to be something. In the absence of any evidence at all, the HN guidelines ask users not to post insinuations about astroturfing, foreign spies, etc. Someone else holding an opposing view does not count as evidence. There is an epidemic of internet madness about this right now, and it's not in the values of this site to succumb. Perhaps everywhere else wants to be James Jesus Angleton in the wilderness of mirrors, but HN, barring catastrophic failure, is not going to go there.
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As for silent downvotes, I realize they sting and are annoying, but that's the way HN works. Users aren't required to explain why they downvote. If we had such a requirement, the threads would fill up with 10x the petty bickering about downvotes, and we have more than enough of that already. The thing to do with downvotes is to examine what you wrote to see what might have been objectionable about it. If you notice something, note the correction for next time. If you notice nothing, muse to yourself about the fickleness of homo internetus and move on. It's not worth posting about, which is why the HN guidelines ask you not to.