Abstracting all communication as "speech" and therefore "free speech" and therefore "censorship" means not differentiating between discussing local traffic policy with a group of informed people, and having everyone listen to the loud smelly drunk who sat down at your table to tell jokes about negroes.
The best forums I've ever been on were those where there were no ratings whatsoever, a linear structure of discussion, and that allowed any range of opinions as long as they were not in the aforementioned groups.
When a small number of trolls can derail a conversation, you get denial-of-service attacks against civil discourse and democracy.
> having everyone listen to the loud smelly drunk who sat down at your table to tell jokes about negroes
For example, the article talks about a mismatch between moderation tools and trolling:
> Internally, Costolo complained that the “abuse economics” were “backward.” It took just seconds to create an account to harass someone, but reporting that abuse required filling out a time-consuming form.