I believe this is the question in which you are referring.
deduping existng leads and contacts
I just went and looked at it and upvoted it. This is however one of those questions that is in a gray area. While I do think the question is valid and provokes some good, intelligent conversation, it could be argues that its not a good Stack Exchange question as there isn't a specific answer. It is somewhat opinion based.
In looking through the helo though I did find this
Some subjective questions are allowed, but “subjective” does not mean “anything goes”. All subjective questions are expected to be constructive. What does that mean? Constructive subjective questions:
- inspire answers that explain “why” and “how”
- tend to have long, not short, answers
- have a constructive, fair, and impartial tone
- invite sharing experiences over opinions
- insist that opinion be backed up with facts and references
- are more than just mindless social fun
I believe the question falls in here which is why I up-voted it.
I guess I can only guess that the down-voter felt the question was primarily opinion based and too broad.
As far as the discussion around down-voting in general, I agree that it should be an unwritten rule that a comment should go hand in hand with a down-vote.