Sometimes reporting technically covers the last one. But usually not. Not all subs have rules against bigotry, trolling, dog whistles, general assholery, etc. I strongly hold it's important that downvoting is an option to deal with these kinda things. It's a way to show everyone that the comment isn't acceptable.

Plus even when reporting is an option, it may not be fast enough. Can't really automate removals, either, as people will abuse that.

Arguably "disagree but acceptable" should just not upvote. In a certain sense, that's already a middle option.