It’s one of these classic situations that reveal the nature of a corporation as being distinct from an individual. An individual might follow the thinking you’ve outlined, but’s corporation comprised of endless layers of competing management, personal fiefdoms, and a collective case of shortsighted, goal-oriented thinking will not. It doesn’t matter if this is terrible for FB as a whole entity, or moderators. The mods aren’t making the call, and the people who do are possibly more concerned with showing they can minimize a source of overhead that doesn’t immediately add to their bottom line.