I've looked at several of his down votes and it is hard to see if any of them are really subject related. most of his large down votes are due to large up votes. One day my thought on the down vote will be adopted and people can see why they got the down vote whether it is for rewards, spam, plagiarism, or what people want to know. It's not hard it involves one more step on down voting but it is highly unlikely that it will be accepted or if it can even be coded, (which I believe it could be).
In your case it would seem the down votes were to counter up votes from @xeldal who seems to be a 100% manual voter when you look at the content he votes for. He votes in three ranges 100%, 50% and 20%, at least that has been what it seems for the last couple of days. Also his votes are spread out through the day unlike haejin and rancho who's votes are all completed within 1 to 2 minutes.
I am of the opinion that he is only voting to counter act what he feels are excessive votes. When he does down vote he seems to try to not wreck a person reputation, that to me shows he really is concerned with the reward pool system and with keeping things balanced.
wake up and smell the vaxtard agenda
I just scanned several pages of them, it seems majority are politically incorrect/independent journalism or conspiracy related, a good chunk are on recipe posts or related to natural medicine/healthy eating/gardening in some way, and a tiny minority on truly random posts that did not seem to fit any pattern. Many users in the independent journalist category are downvoted multiple times. Many of the downvoted posts are in fact not upvoted by haejin or rancho, although a good number are. This is what I noticed, seems to be a pattern to me, a pattern of the type of posts deemed to not be worth high payouts anyway - namely recipes and politically incorrect views. Those are my observations, I'll be putting a post together on the subject shortly...