Humans aren't deterministic. Determinism is a red herring. There are lots of other problems with agentic programming, but this is not at the top of the list.
Thus why we replaced computers (flesh and blood people writing out calculations) with computers (silicon-based number-crunching machines).
It doesn't matter what we are, what matters is what we want, and whether what we built actually works the way we want it to work.
[0] Discworld's Ponder Stibbons would be rolling in his, grave, or more likely his "Early Death package" pocket-dimension jar.