For the same reason that all central planning ends up being unwieldy - the world is complex. It's not the work of doing the reviewing itself that is unsustainab

For the same reason that all central planning ends up being unwieldy - the world is complex. It's not the work of doing the reviewing itself that is unsustainable, but rather crafting some singular policy that can reject all "bad" while allowing all "good", compounded by having to work with governments/corporations/etc that want increasingly fine-grained censorship.