isn't it because there are too many contradictions and ambiguity? the reason it works for humans is because we don't apply everything at once either.
How many arbitrary rules can you memorize? Do you even remember them two years later? If you do, then we can get to your statement.
And your statement is true. Humans do not run every action through a memorized list of rules, to see if any of them block the action. We don't. We're not going to, either, no matter how badly the policy manual writers want us to.