Quoting from the conclusion: "People are irrational yet believe they are perfectly sane. They will take personal offense any time anyone attempts to expose the disconnect between reality and their own delusions."
I'm sure everybody has a negative reaction to receiving a flag on a post or comment, myself included. My first thought is always "What did I do?" that has to be interpreted in the sense that I've either done something wrong or am being maliciously acted upon.
While it won't fix the full issue, just by having an explanation of the flagging (or even negating a vote) can calm a lot of the emotional response and ideally gain some concept of the other persons point of view. Especially in presidential politics, I see so many assume that counter (and negating) voters are instantly viewed as being malicious, leading to highly emotional reactions (which can only be calmed before having a logical discourse.) I've seen many posts around that would require a flagger to choose a category, or maybe even require a typed response of a minumun number of characters. I see importance in making the person flagging think and verbalize what their line of reasoning. One this makes abuse or revenge flagging much more obvious, as well as potentially minimize the 'negative emotional' reactions people feel when seeing said flag.
I've never been a fan of us/them splits whether is US politics or even on this site. If we truly care about the future of a country/world or even this site, there are always shared fundamental goals that tie us together. The perception of malice incite poor reactions (in my opinion) and calm logical discourse (even when there is disagreement) is a major part of the fix. We're all in the same boat together.