I realized a generalization from recording up and down vote total separately is to have a few categories of vote. Perhaps a post could be voted "up" "down" "agree" "disagree" "troll". In a system like this, it would be troll votes rising above a relatively low threshold that would grey-out or hide posts and comments.

I think this is somewhat clunky compared to just reporting up and down separately. But I wanted to throw the idea out there for those who wish to think about this question.