8chan literally had sub boards dedicated to child pornography. Kiwi Farms is where people make fun of other people. They're really not comparable unless you believe "not being made fun of" is a human right.
This is meant to be sarcastic but a lot of people basically do believe this. Most arguments about "stochastic terrorism" would implicitly aim to devalue/censor any sort of speech that "punched down".
With all of this, it's clear that if you're going to argue that stochastic terrorism even exists, you should believe that it is happening at Kiwi Farms. Incredibly personal, incredibly specific (doxxing), directed at marginalized people, and in a space full of people that are already predisposed to acts of violence.
Indeed they do, and they're free to go on arresting their fellow citizens for teaching dogs offensive gestures. But Cloudflare is an American company, and they're under no obligation to enforce politeness on their customers.