Haejin was gifted with nearly 11K worth of upvotes in about 3.5 days over 33 posts from a single user. I believe a dispute over the amount of rewards to be a very good reason. I don't agree that your post should be downvoted for simply disagreeing with someone. Now, I would be fine with someone downvoting your comment with the belief that it isn't worth the .52 that you self-voted, but I don't think it should be made to disappear unless you use offensive language that a sufficient number of the community has requested be minimized.
Go to steemworld.org/@haejin and refresh the coming author rewards section. He is still scheduled to make $ 6,667.46 in the next 7 days. worth a market value of 27,353.15. While you're there, take a look at the downvotes he is receiving vs the upvotes he is getting.
To address your last statement, I pretty much do that and have not downvoted haejin, but if he is taking a big piece of the pie,he does so at the expense of everybody else. If his pie is voted on by many different users, I don't see much of an issue with that. If it is because of a single user, that deserves attention.