Imagine if signing up to read Twitter was free, but posing required you to spend a week doing moderation first.
Everyone who came into the community would have to learn the rules before they violated them.
Then, when you’re tempted to break the rules, you’d remember that there were people who would read what you wrote, just like you did for others, and you’d lose your account and have to do another week of moderation before getting to post again.
This is not too hard to implement. It’s certainly easier than inventing a magic AI that will solve all your problems. It just requires that Twitter care enough about their community to do it.