Except for backup purposes, why do you think I'm talking about everyone hosting everything? Hell, I hope you realize that the way Lemmy works now, instances are just copying other instances content and the issue you're talking about is a reality that could be circumvented by the solution I'm proposing?

You realize that's already how websites work, the content is spread over tens or hundreds of servers, they're just all owned by the same company.

What I mean by "get rid of" is that server admins need to use tools to clean up illegal content from their servers. Lemmy admins are doing that, right now, if they don't want to end up with CSAM on their server, even if they host an instance that doesn't allow NSFW content. Without using tools to clean up their server, NSFW content will end up on it.