I used to be very excited about Stack Overflow. I even started to make it a habit to routinely check for questions with certain tags to try to provide answers. And I did.
Then this happened:
In this question, I felt I had provided an answer exactly as the OP had requested it, where the other answers had not, and since this wasn't obvious, I took the time to point out the flaw or shortcoming of various answers. The end result was 4 downvotes and 0 explanations, of a perfectly valid answer which really was most faithful to what OP had asked.
Then this happened:
I provided a simple, concise, very efficient algorithm, completely from scratch and not depending on external libraries, that was faster than most other solutions posted (except one that just called an external library). I received 0 upvotes. The other answers, most of which were slow, and inefficient, and lazy, all received a number of upvotes (14, 7, 3, 0). The only difference is that the other answers had been posted by users of higher reputations, making them seem more "legit".
Today, this happened.
Two bad anonymous downvotes on a question on which I had taken every effort to make clear, detailed, concise, and so on. I have politely asked for an explanation, but none of the cowardly downvoters have cared.
Why is anonymous downvoting allowed, without a required, if anonymous, explanation? This can completely shatter the experience of new vulnerable users, possibly turning them away from the site as well as their potential contributions.
I have honestly mostly stopped looking for questions to answer, my reputation has stagnated, and I feel this can be the case for a lot of new users who do have a lot to contribute and are discouraged by the abuse of some of these features. I do not see it necessary to risk alienating them in this way during their vulnerable initial stages with SO.
Anonymous downvoting serves well the SO establishment, the users with already comfortably high reps who do not feel the pain of downvoting others. It also serves well the lazy who do not care to write even a short sentence on why they think the question/answer which they downvoted is bad or how it could be improved (which should be everyone's goal).
It also serves well cowards who downvote out of spite or retaliation.
Why is anonymous downvoting a feature in SO? In particular, the feature request here is to enforce a short, optionally anonymous explanation/comment required from the downvoter (something that doesn't have to take more than 2 seconds to type, maybe "misleading title", or "homework problem"). If you care enough to downvote the effort that someone else has put forth, then you can at least be bothered to give a short explanation of why. Such an explanation could be visible to only the downvoted user and to moderators, who could then use these to control the abuse of the feature.
Note: There is the argument that disclosing the identity of the downvoter could enable retaliative downvotes, but this is not necessary. Requiring a short, anonymous comment by the downvoter would keep his anonymity, as well as help the downvoted understand what he could do to improve. It would also deter unjustifiable (revengeful, spiteful) downvotes.