I agree that it is useful to comment on the shortcomings of a particular node, especially when it is a mistake that isn't readily apparent. However, I don't particularly like replies that say "I voted -- on this node because...". There is no reason to let people know how you voted on a node at all, in my opinion. This leads to the pattern of monks thinking "Look, this really experienced monk voted --, I'd better do that too." A slew of downvotes rather than a few don't make the point any clearer, they just beat the monk while s?he is down, and possibly chase away newcomers.

When's the last time you used duct tape on a duct? --Larry Wall