By evidence I mean something in some data somewhere that's more than just the opinion being posted, which we can look at and evaluate objectively. I know that's a bit of a lame answer, but I can't give you specific examples without giving the same examples to others who would want to circumvent leaving evidence in that way.
The main thing to understand is that we need something to look at other than just an opinion that one commenter was expressing which another commenter didn't like. That's evidence only of difference-of-opinion, not abuse.
Such data isn't always secret and isn't always just on HN. For example, if someone is asking for HN upvotes on Twitter, we sometimes get links from eagle-eyed HNers. Similarly when someone is sending out spam emails trying to organize a voting ring. And sometimes spammers copy comments from other forums and paste them into HN. Those are pretty basic examples but I hope you can see that in each case there is some objective data that supports a judgment of abuse.
Conversely, suppose you like $BigCo and someone else hates $BigCo, sees your comment praising them, and replies "how much are they paying you, shill?" That's the kind of thing we don't allow, because there's literally nothing supporting that judgment. The same type of commenter will see various comment arguing for $BigCo in HN threads and then post to other threads with high confidence that "HN is overrun with astroturfing". What they mean is that it's overrun with comments they don't like—and even then, "overrun" is an exaggeration.
Thank you so much, dang. I'm completely with you 110% that just throwing accusations this way is bad, and that it's also most likely a "I couldn't disagree more" leading people to a wrong conclusion about shilling and such.
What about the other side of it though? your reply didn't really address it.
What I feel is happening now is that in those situations (and others), people downvote and flag things that they don't agree with. They're not shouting "shills / astroturfing" yet the collective power makes it easy to silence opposing opinions, especially if those opinions are in a minority.
Completely anecdotal, but I reported to you two cases of flagged stories that in my opinion had value in them for the community (and in the discussions around them). Those stories were effectively silenced. I think it's a shame. There's no evidence require to flag or downvote, there's no requirement to even give an argument/reasoning for doing it.
Are there any plans to tackle this kind of behaviour in a similar way that empty/non-evidence-based claims of astroturfing and shilling is dealt with?
The main thing to understand is that we need something to look at other than just an opinion that one commenter was expressing which another commenter didn't like. That's evidence only of difference-of-opinion, not abuse.
Such data isn't always secret and isn't always just on HN. For example, if someone is asking for HN upvotes on Twitter, we sometimes get links from eagle-eyed HNers. Similarly when someone is sending out spam emails trying to organize a voting ring. And sometimes spammers copy comments from other forums and paste them into HN. Those are pretty basic examples but I hope you can see that in each case there is some objective data that supports a judgment of abuse.
Conversely, suppose you like $BigCo and someone else hates $BigCo, sees your comment praising them, and replies "how much are they paying you, shill?" That's the kind of thing we don't allow, because there's literally nothing supporting that judgment. The same type of commenter will see various comment arguing for $BigCo in HN threads and then post to other threads with high confidence that "HN is overrun with astroturfing". What they mean is that it's overrun with comments they don't like—and even then, "overrun" is an exaggeration.