Pick a model, a seed, a temperature and fix some floating-point annoyances and the output is a deterministic algorithm from the input.
Events are either caused, or uncaused. Either can be causes. Caused events happen because of the cause. Uncaused events are by definition random. If you can detect any real pattern in an event you can infer that it was caused by something.
Relying on decision making by randomness over reasons does not seem to be a good basis of free will.
If we have free will it will be in spite of non-determinism, not because of it.