Given that some of us have been getting uncommented downvotes on our answers - I alone have had 7 in the past two days - I'd like to know a little more about this user and the faults (s)he apparently sees in our answers (and questions).
A user can reveal as much as they want about themselves, and I think it is appropriate to respect the boundaries of what a user reveals about themself. If someone suspects a user to violate the rules, contacting the moderators is a prudent thing to do.
There have been several meta discussions on downvoting without accompanying comments, and the majority position seems to be that this is legitimate. For the point of view of someone who "downvote[s] quite generously, and rarely comment[s]", see here.