The best (but not necessarily good) answer I see is that ad supported social media can’t meet the minimum bar for effective moderation and be profitable, then it should be shut down as a nuisance. Not all business models have a right to exist.

Perhaps if free/ad was not workable we could see subscription services with better moderation. If not (people won’t pay), then it’s not actually worth that much to users so it’s fine to let it die.