Those activities are certainly prohibited. I don't think we don't need a guideline to say that though.
The HN guidelines don't list everything that's prohibited. To publish such a list would be to imply that everything not on the list is ok. That would be a big mistake! It would be carte blanche to the entire internet to find loopholes and wreak havoc with them.
> Sometimes the pattern is overwhelming.
The trouble is that in many cases it feels like such a pattern—and the feeling can be super convincing—yet there turns out to be no evidence for it. Perceptions are awfully unreliable about this.
We ask people not to post about these things in the threads, not to imply that actual astroturfing etc. is at all ok, but because unfounded comments about it vastly outnumber well-founded comments. Worse, they have a way of proliferating and taking over the threads.
Keep in mind that that guideline doesn't say "please don't post and then do nothing". It says "please don't post, but do email us so we can look into it". We do look into it, and on occasions when we find evidence, we act on it. There just needs to be something objective to go on, and in most cases there isn't.
The phenomenon of internet users being far too quick to jump to conclusions about astroturfing, bots, etc., is extremely well established. If there's one phenomenon we've learned about decisively over the years, that's the one. (Well, one of two.)
Btw, I've written about this a ton over the years (https://hn.algolia.com/?sort=byDate&dateRange=all&type=comme...). I particularly remember writing these two:
https://news.ycombinator.com/item?id=35932851 (May 2023)
https://news.ycombinator.com/item?id=27398725 (June 2021)
They're long, but they still hold up as descriptions of these phenomena and the moderation approach we take to them.