Though much has been discussed on the topic, I consider down votes to be for those comments that don't contribute to the discussion, even if I might agree. In your case, however, I not only disagree, I don't feel your comment has contributed positively to the discussion. Whereas the parent comment did bring a different viewpoint to the discussion, though I might disagree with them.
In conclusion, have a down vote. Parent: have an upvote.
I'm happy with that. I was just kvetching really (and I didn't actually downvote). I strongly feel that votes should be used as you statrd., and not in lieu of a reply expressing disagreement through the courtesy of a reply. my complaint really is that downvoting is so capricious. people who hate dogs in the office downvoted me for saying that dogs have not been a problem at my office. the statement was factual, respectful and related. meanwhile I can say some snarky thing and get upvoted like crazy. it's just silly