A computer program takes digital bytes, runs some discrete logic on them, outputs some more bytes. Laws take messy real world stuff, run some subjective decision tree on them, and output some messy real world actions to take. If you model the former with the latter you end up 'shelling out' to human judgement every 2 words. Suppose you accidentally shoot somebody while duck hunting, the meaning or value of pretty much everything here can't be determined by a computer, so the code-law version of this random snippet of natural-language-law would be pretty useless:
> If it is found that the defendant did the killing or wounding, but that it was not intentional or negligent, the court shall dismiss the proceeding. Otherwise, if it is found that the defendant did the killing or wounding intentionally, by an act of gross negligence, or while under the influence of alcohol, the court shall issue an order permanently prohibiting the defendant from taking any bird or mammal.