Organized scalable social moderation is as doable with centralized services as it is with P2P.
The difference is that a centralized service has at least one person that must be responsible for content, whether or not they moderate it adequately, whereas, with a P2P service, each user may effectively run their own service and must be responsible for its content, whether or not they moderate it adequately.
P2P would seem then to have more scalable user-invested moderation. Unfortunately, some using these services think they’re in the internet equivalent of a bohemian nudist colony. That’s not how it works, though. The responsibility is heightened, not lessened.
The difference is that a centralized service has at least one person that must be responsible for content, whether or not they moderate it adequately, whereas, with a P2P service, each user may effectively run their own service and must be responsible for its content, whether or not they moderate it adequately.
P2P would seem then to have more scalable user-invested moderation. Unfortunately, some using these services think they’re in the internet equivalent of a bohemian nudist colony. That’s not how it works, though. The responsibility is heightened, not lessened.