I guess I'm late to this post, but I wanted to respond to this:

"...we should get rid of downvotes so people like this can operate unmuted on HIVE please let me know in the comments."

DV's, as you are observing, don't discourage spam. Spam isn't intended to rake in rewards, so taxing them doesn't confront them. There are other mechanisms that could mute them besides DV's, I can think of several. There is a mechanism that does prevent spam from being revealed by the frontends, but it is global, IOW nobody on the frontend would see the muted comments/posts, so it's reserved for spam so severe it causes the bandwidth to be used up and the chain becomes barely usable. DV's are particularly useful when people care about the rewards for their posts and comments, so mostly plagiarists, self voters, and botters/circle jerks, and the like. Taxing their rewards counters the purpose of their malicious acts, so effectively discourages them.

Thanks!