I do understand and agree with the rest of the post. By all means, downvotes do have value with dealing with immature or agenda'd posters if that is problematic to a community.

But I did state why it can be fine and how there's a reason why upvotes require no reasoning while downvotes do - they have an immediate, positive effect on the usability of the site (everyone sees top posts), while downvotes have a less immediate one (only a subset scrolls to see bottom posts). Upvotes are just inherently more valuable to the community on the whole and shouldn't be put to equal questioning. Downvotes are more useful to contain undesirables.

On this note, there's somewhat of a tangential discussion to all of this, which is "should posts that go below a threshold (like -10 points) be hidden from users by default?". I personally would opt to keep posts visible to myself, because I want to know what was said that earned the shunning. But I can't think of a reason why a system that has downvotes shouldn't do that filtering, after all, it basically empowers downvotes to do their job better, and stops trolls from latching to top posts.