The problem with putting machines in control, is that it centralizes power. In these kinds of complex situations, I would rather have thousands of humans each making suboptimal decisions, than decisions by half a dozen algorithms designed by a small group of people.
It's the same reason many people oppose electronic voting. Sure, letting humans count votes seems inefficient, and might enable some small scale fraud, but it's much more difficult to commit large scale fraud if there are many people involved. When you use voting machines, you put a tremendous amount of power into the hands of the people who design and build those machines.
It's easy enough to make the machines open source. And anyway, I can't imagine there is any incentive for there to be some kind of mass conspiracy involved here.
It's the same reason many people oppose electronic voting. Sure, letting humans count votes seems inefficient, and might enable some small scale fraud, but it's much more difficult to commit large scale fraud if there are many people involved. When you use voting machines, you put a tremendous amount of power into the hands of the people who design and build those machines.