[incision]

>"I hope downvoting has nothing to do with a agreement; I thought it was for comments that aren't valuable to the conversation (e.g., not substantive, poorly reasoned, false, or poorly communicated)."

I agree.

Thing is, the "when to downvote" debate is ancient at this point and no closer to consensus.

These days, I'm given to thinking that any voting system should assume the behavior of least resistance, that it's thoughtless, reflexive and therefore only potentially valuable after being sanitized / aggregated / weighted.