"Zach", if that his real name, seems to a moderately big cheese in LW. Grepping through the comments of Why it's a good thing I'm a bastard led to this fascinating(?) meta-post, which tells me that just being rational is in no way a sure-fire way to avoid conflicts:

https://www.lesswrong.com/posts/9DhneE5BRGaCS2Cja/moderation-notes-re-recent-said-duncan-threads

Said and Duncan are both among the two single-most complained about users since LW2.0 started (probably both in top 5, possibly literally top 2). They also both have many good qualities I'd be sad to see go.

The LessWrong team has spent hundreds of person hours thinking about how to moderate them over the years, and while I think a lot of that was worthwhile (from a perspective of "we learned new useful things about site governance") there's a limit to how much it's worth moderating or mediating conflict re: two particular users.

(tangent, the fact that LW allows straight double quotes instead of changing them to curly ones really grinds my gears)