Ever consider the fact that maybe @ranchorelaxo is a whale who finds Haejin's content useful and has made a ton of money off of it and this is his way of paying him back?
Haejin is making amazing content for FREE and is getting rewarded by the people he is helping. So what if one guy decides to only upvote his content? That's his choice.
Actually, yes. I mention that exact possibility. It is a reply somewhere on this page.
It is also everybody else's choice to reverse that action. The reward pool is shared by all steemians and directed by all steemians. If people feel the reward is not appropriate, they have just as much right to correct that reward.