Technical workaround:

Make it so that you cannot upvote/downvote from a user's comment history page. Or rather, show the vote as counting to the person pressing it but don't actually tally it.

EDIT: Ok, I see that the buttons have been taken off so this is irrelevant. In that case, new proposal: put the buttons back but make them do nothing. The majority of LW won't read this post and I think you'll be able to fool those who go to mass-downvote comment histories.