If somebody sees an on-topic comment they disagree with, and posts "I disagree" with no further explanation, that's not adding value to the discussion. If some

If somebody sees an on-topic comment they disagree with, and posts "I disagree" with no further explanation, that's not adding value to the discussion. If somebody sees an on-topic comment they disagree with, and downvotes it with no further explanation, that's not adding value to the discussion. If somebody sees an off-topic comment that doesn't add value to the discussion, they should downvote it so that other people won't be distracted by it. Adding a comment saying "I downvoted you because your comment was off-topic" would add even more noise, so don't do that.