I can't imagine how this follows. Obviously, existence must be non-deterministic if any subset of it is non-deterministic. That is a tautology. As for the political and ethical implications of free will, there are none.
The widely reported cases where a criminal "gets off" due to diminished capacity are simply extensions of legal thinking that is centuries old. We are in an age where the working of the brain is partially understood, and courts are doing what courts do -- judging. Perhaps judging badly in some cases, but that's the way the world works. In any case, free will is dependent on correct brain function, and there are such things organic brain diseases and dysfunctions.
I can't imagine how this follows. Obviously, existence must be non-deterministic if any subset of it is non-deterministic.
The burden to substantiate that strong determinism is not the polar opposite of free will is to prove sufficient randomness in the physical laws to give rise to the observed diversification of the universe.
I aver that you are left with Brownian motion, which is but a causal effect, i.e. the "consequence of ongoing bombardment by atoms and molecules."
Randomness is tricky per se.
Strong determinism doesn't have any more to do with diminished capacity than brilliance. It just means that, under strong determinism, nobody can be responsible for what they do because there is no free will.