It is fine to upvote someone you like. Normally it is good.
Unfortunately, Haejln is working with a whale to gain HUGE amounts of Steem. $300 per post for 10 Posts a day is crazy.
Maybe some of his work is worth $300. But not 10 Posts EVERY day.
He is greedy. Because he does this then he hurts everyone.
If he really cared he would be generous and give away $5 upvotes to his followers. But he doesnt. He only upvotes himself. Then he asks you, his followers, to upvote him more and more.
His behaviour is bad. Steem was made to help everyone, not just for a few to EARN HUGE SUMS of money.
He wants followers to make him rich. But good steemians want community to help and support each other.
I hope this helps. Good luck to you!