I don't feel bad for the guy, I just think it's an eye sore to stand near or above posts that show better outputs as it just sends a message on what the platform wants to value, or just the community. But those situations are mostly from curators that have ties to the author rather than an organic tip from strangers. If people lost money each time they upvote, we would see less voting activity unless its a self vote.
It's not permissible to just downvote a post because you don't like a content? But it's ok to upvote because you like the content? Idk, blurt seems to be a wonderland for having no downvotes and their trending has a lot of trash content.
Well, let's put it this way: you're always free to use your downvote, since it's yours. I never do, as I realize its effects can be taken quite seriously (as I know I would take them). But ultimately it's up to you what you do with yours. Still, I would recommend you to give an explanation for your downvote, because not knowing how I deserved it would bother me more than the loss of rewards.