And the human beings who use them to produce code don't produce deterministic results either. Current harnesses have come a long a way to make non determinism not be a problem for quite a few areas. And the scope keeps increasing every day.
Yet nevertheless, both e.g. syntax highlighting and intellisense have been heralded as things that "fry ur brain". So have high level programming languages by the way.
To give you a particularly specific example, Rob Pike really wants you to know that if you use syntax highlighting, he thinks of you as a child.
AI is as deterministic as a human programmer. A programmer who is burned out and has not slept well produces code of a different quality than a programmer who has slept well and is highly motivated. That's hardly deterministic. AI can be made deterministic enough if you have strict quality gates, just like with humans.