If you care about moderation, a lot of it has to be done manually. Manual moderation requires placing a high level of trust in the moderators. That means that either you pay them well enough to care, or you build a community which user-moderators will protect. Or both.

That makes approximately all business ideas to host user generated content non-viable. The conflict is dynamic and you are the Maginot Line...except that any breach of laws creates a potential attack by state enforcement agencies too.

To put it another way, ASCII files and a teletype were enough to see pictures of naked ladies. Good luck.