Yeah, Polycentric lets server operators choose to censor individual posts or entire users. Your client can query anything that's censored from one server by querying it from another where the content was published. It's fairly easy to tell when a post is censored since each post has a logical clock per user that is incremented per post, so you can pick out any missing logical clock entries.
The key is to never let anything like a central party impose censorship that can't be overruled by the user, but still allow them to filter out 99% of the crap by default.