> The eternal question of tech platforms - should we be responsible for what users post?

I would never say a platform has to be responsible for what a user posts, and to be clear, I mean either a user of the platform, or a user of the platform's ad tooling, or anything else. Anything that arrives via an upload button of some sort. However: If you as a platform then distribute what has been posted, yes, you are responsible for it. Your service is now broadcasting that content. If that content is harmful, you should be held responsible.

Who else conceivably could be? And if the response to this is "well we have way too much stuff coming in to moderate it" okay, then restrict how much stuff comes in. Require approval on individual posts or on accounts.

Like, this is such basic shit. If a newspaper printed CSAM on the front page, they would be arrested within the day. But because Facebook is real super big they just don't have to take care of their house? Ridiculous.