They just need to stop plagiarising, spamming, farming, etc. and they'll get forgotten very quickly. Many have changed their behaviour which is great news for everybody but unfortunately a handful decide to continue and consequently, continue to get downvotes - in this instance, to his multiple accounts.

This particular user has decided to continue and we enjoy a daily exchange of downvotes. Unfortunately, there's no way of anticipating which of his posts or comments he will choose to upvote from his other accounts so they all get the same treatment, hence the apparent blanket of downvotes. As you can see from his reply and having previously exchanged opinions on this matter, we share polar opposite views on each others' behaviour so I expect this to continue.

As you know, I work with transparency and this post has a bit more detail regarding this particular user -
https://steemit.com/hive-108572/@endingplagiarism/r351574nc3-s-farming-operations