"It's clear from the data that they reliably downvote jerks and trolls"
Most people know what a jerk is. Perhaps though you (and others) could define what a troll is for the purpose of interpreting this statement. (Of course I know the online definition [1] but think that there seems to be much latitude in "extraneous, or off-topic messages" or "starting arguments".)
Specifically also from [1]:
"Application of the term troll is subjective. Some readers may characterize a post as trolling, while others may regard the same post as a legitimate contribution to the discussion, even if controversial."
While as mentioned I know what a jerk is, I can also see very easily someone throwing out "troll" to stifle someone else in more or less a parental way. That is to nominalize something as simply not important or worth even of discussion.
The more I think about it, the more it seems like a mistake to nail these terms down precisely. If we try to, then whenever a comment doesn't match the definition, people will argue that it must be ok because it doesn't technically break the guidelines. That's not what we want to encourage. We want HN to be motivated by the spirit of the law more more than its letter.
It's true that "troll" is ill-defined. Perhaps we can try not to use that word. I like the phrase "toxic comments" because, while imprecise, it conveys what those do to the ecosystem. In practice, I'm not sure this is as big a problem as it seems. As Sam pointed out, the bulk of the community has little trouble recognizing these things.
I think some of the lessons from "Raising a Moral Child" from two days ago fit here. We tell people "don't be a jerk or troll", but when an individual makes a toxic comment, we tell them "you're a good person, even if you wrote a toxic comment, and we know you can do better".
Most people know what a jerk is. Perhaps though you (and others) could define what a troll is for the purpose of interpreting this statement. (Of course I know the online definition [1] but think that there seems to be much latitude in "extraneous, or off-topic messages" or "starting arguments".)
Specifically also from [1]:
"Application of the term troll is subjective. Some readers may characterize a post as trolling, while others may regard the same post as a legitimate contribution to the discussion, even if controversial."
While as mentioned I know what a jerk is, I can also see very easily someone throwing out "troll" to stifle someone else in more or less a parental way. That is to nominalize something as simply not important or worth even of discussion.
[1] http://en.wikipedia.org/wiki/Troll_%28Internet%29