Consider a global human population, fractured into historically formed nations and power blocs. Consider corruption and clans taking up a fraction of positions of power at a certain duty cycle. It's unavoidable legislative bodies would eventually abuse control of technology, for those points in time yes, doing the right thing becomes doing the illegal thing, but only because corruption attained such powers.
> Otherwise the economies do not make sense.
The economics at what scale? At scales of earthly compute, earth is cheaper and more maintainable. At stellar scale, the power simply isn't available on Earth, so the most economic path is whatever is the most economic space ML datacenter path.
Militaries.
On the ground nothing harms your own infra by dropping a bomb on another datacenter that might be powering the opponents entire military strategy.
Terrorism threat is nonexistent now, but maybe not in the future.