My answer: Generally, yes.
WikiTree is all about communication and collaboration. Sure, sometimes there's a really obvious question/answer that's usually very negative and it's obvious why people are downvoting it.
More often than not though, the poster of the question/answer is left wondering what caused someone to downvote it.
I think it would be helpful and considerate if you are going to downvote a question/answer, to at least be willing to state why you felt the need to do so. (This could all be said for upvoting a question too.)
If things are downvoted but no reason is given how can there be change and improvements?
I personally would hope that any WikiTree member who would downvote a question/answer would give the courtesy of explaning why.
I would also hope that any WikiTree member who downvotes questions/answers just for the sake of downvoting them and without legitimate reason would stop and ask themselves if that's really in-line with our Honor Code and adjust their behavior accordingly.
I'm so grateful that we have this forum and so appreciative of you generous WikiTreers who devote so much time to posing and answering questions to help improve the site, lifting up others with your postiive friendly comments and helping others with their genealogy. In my not so humble Forest Elf opinion - we have the BEST community on the internet :)