I think the purpose of the 'overall karma' button on comments should be changed.
Currently, it asks 'how much do you like this overall?'. I think this should be amended to something like 'how much do you think this is useful or important?'.
This is because I think there is still a too strong correlation between 'liking' a comment, and 'agreeing' with it.
For example, in the recent post about nonlinear, many people are downvoting comments by Kat and Emerson. Given that the post concerns their organisation, their responses should not be at risk of being hidden - their comments should be upvoted because it's useful/important to recognise their responses, regardless of whether someone likes/agrees with the content.
I think a nice (maybe better) heuristic is "Do you want to see more/less of this type of post/comment on the Forum?"
I worry this heuristic works if and only if people have reasonable substantive views about what kind of thing they want to see more/less on the Forum.
For example, if people vote in accordance with the view 'I want to see more/less [things I like/dislike or agree/disagree with], then this heuristic functions just the same as like/dislike or agree/disagree vote (which I think would be bad). If people vote in accordance with the view 'I want to see more/less [posts which make substantive contributions, which others may benefit from, even if I strongly disagree with them/don't think they are well made]', then the heuristic functions much more like Matt's.
Note that I downvoted their response (intentionally separating it from agree/disagree) because I saw them as attempts to enforce a bad norm, and some of them as a form of intimidation. I endorse downvoting them (and also think other people should do that).
I agree with your high level point but not necessarily the example you give - I agree with Habryka's reasoning.
I have seen a handful of instances of people writing what I believe are useful contributions that might spark a discussion, but are controversial being downvoted.
Saturday night fun: ineffective fundraising
I've been rewatching an old 90s British satirical news programme, and came across this brutally brilliant sketch. It's almost proto-EA
It was funny until he insulted her appearance. Then 🤢
Yeah, he's not supposed to be a pleasant character, and is typically satirising some of the nastiness of the British press (both then, but still relevant even now). In another episode his interviewing technique caused Australia and Hong Kong to declare war on each other: