"Please don't post insinuations about astroturfing, shilling, brigading, foreign agents and the like. It degrades discussion and is usually mistaken. If you're worried about abuse, email us and we'll look at the data."
It would be much better to show useful statistics to convince people that bots are kept to a minimum.
I think even if you were to present statistics of some kind, some people might not consider it enough and ask for some different contrived set, on and on, forever.
If you think something's really wrong, you email the mods about it. Otherwise you get in this exact meta-discussion land about what is astroturfing, what are accusations, and so on. And then you get threads that distract from meaningful conversations, on and on, forever.
Maybe we could all just try to discuss the article and related comments by refuting/agreeing with their central points. It would be less boring than seeing the same metadiscussion and flailing forever.
(In that vein, I won't be replying to this comment further)
edit: for those left wanting, take a look at the words of 'dang: https://hn.algolia.com/?query=by:dang%20astroturfing&sort=by...
If it happens a lot and without a given reason it certainly does, but it isn't such a black and white issue that it has to be stopped at all costs. When someone points out very suspicious patterns over multiple names, comments, similar threads that are more likely to have astroturfing or bots etc. and mods pop in to say not to talk about astroturfing and bots because it doesn't happen, that's not helping keep the site to a higher standard.
I don't doubt it is a priority and people are working on it, and I don't think the reply here that has no examples is worthwhile, but an all or nothing attitude doesn't help, because it is the reality of the internet.
It's also not so much about trying not to make "the site look bad", it's more that it generally leads to baseless witchhunts and flame wars.
HN has an advantage over Twitter and other social networks: posts are supposed to be insightful instead of merely pictures of cats or people doing funny tricks. As a result we can criticize posts based on their intrinsic values instead of having to go meta and wonder about the intentions of the person posting them.
If a bot manages to posts dozens of interesting stories that make it up to the top of the front page every day I say we keep it...