I think this is a solvable problem. although its not as easy as other social media because nostr is built to be censorship resistant.
The job of removing Illegal content will probably fall on the relay ( maybe with help from users with reporting )
As for removing content in communities I think the same applies since communities can specify which relays they are primarily using. Although for muting/banning one-off posts or users some kind of "community mute list" might make sense. thoughts nostr:npub1lunaq893u4hmtpvqxpk8hfmtkqmm7ggutdtnc4hyuux2skr4ttcqr827lj?