Also good points for downvoting, but it feels really bad getting downvoted, and not knowing in the first moment what happened, why getting downvoted, only getting the information after replying back and forth. I think downvotes also work differently on hive like on reddit. On reddit users are more used to downvotes whereas here it feels more like a flag, removing rewards, appreciation etc.
I know it's not a good excuse, but the problem/practice of self-voting is much more far spread than most users think. 
I think if we agree to ban self-votes, account farming, vote selling, bot delegations to self-upvote a group of users only, we should do it for all users not just a few, randomly picked.
RE: Downvote Drama: Do regular quizzes, giveaways and competitions create value on Hive? Do downvotes destroy the platform? My consequences.