Ideally, we'd have two moderation options: a post quality moderation that's summed up, used to hide trolls and flamebaits and not otherwise shown, and an agreement moderation that's not summed up but displayed for everyone to see.
I upvoted you because I'm in agreement that this is how it should be in an ideal world. I just don't think it is helpful in practice.
The problem here is that people tend to either pick "Agree/High Quality" or "Disagree/Low Quality". These two axes are not orthogonal within the voter's mind.
Given a high correlation, the extra axis only increases complexity without much benefit.
Suppose you had two axes on which to vote (Quality/Agreement) but you only got one vote? If people were forced to pick which axis they speak of, maybe it could allow for more discussion on otherwise controversial topics? I'm imagining a scenario were registering your agreement/disagreement is easy, ala reddit, but saying something about the quality of a post is harder, maybe some threshold of standing in the community, ala hackernews.
I upvoted you because I'm in agreement that this is how it should be in an ideal world. I just don't think it is helpful in practice.
The problem here is that people tend to either pick "Agree/High Quality" or "Disagree/Low Quality". These two axes are not orthogonal within the voter's mind.
Given a high correlation, the extra axis only increases complexity without much benefit.