The only way for the community to handle abusive flags, is to have an auto comment generated by the down vote. Then if the down vote was abusive, the community can counter with a down vote on the original down voter.
My own personal feelings about the down vote is that a comment must be generated, I have heard the counter we don't mandate a comment for an upvote, why a down vote, and it has never mattered how often I pointed out a down vote is a negative action, the argument is a down vote is not a negative argument.
So the addition of an auto comment for any down vote will never be made, thus we as a community will never be able to deal with the blind down vote accounts. (account that have only down voted, thus no retaliatory down votes can be given).