I think this thread is actually a great example, though maybe not in the way you intend it.
When I look at the tone of the downvoted/flagged "dissident" comments (not a value judgment, just an objective description of perspectives that are not generally well-tolerated in intelligent, cultured, Western circles today), and compare it to the tone of the "normative" comments, I see very little difference.
They are both slightly snarky, hostile, exasperated and dismissive. If I was moderating on tone to oppose conflict, I would not like seeing either kind of comment. But I would not consider this tone level worthy of the Giant Banhammer.
But the banhammer is applied very asymmetrically -- both by voters/flaggers, and by moderators. Or so it appears to me.
The result is a context in which "dissidents" feel like they're essentially sitting in the back row next to the teacher's pet. Any time Jamal has a spat with Andrew, the teacher's response is the same: "Jamal, why did you hit Andrew!" "Jamal, stop being mean to Andrew!" But Andrew can say pretty much anything to Jamal.
And both sides argue vociferously that the teacher is unfair. Jamal feels it's unfair that the rules seem to be different for him and Andrew. Andrew feels it's unfair that Jamal, that annoying idiot, is even allowed to be in the same class as him.
It's relatively easy to adopt "both sides complain about the teacher" as the definition of "the teacher is just enforcing fairness and good behavior." But in fact, whatever the teacher draws the line, one side will always want it farther to the left, and the other side will always want it farther to the right.