Why am I happy? They could be clearer. Yes, they could, but that gets into legalism, and that opens loopholes and produces unreadable policies. Eventually we wind up with something completely clear, yet functionally useless.
Many laws are unclear for a reason. If you make the law too rigid, then those enforcing it do not have the leeway to decide how to implement the law. They can too easily be stuck implementing the law against people who should not be the intended target, or the intended target is using loop-holes to get around the law. By making their policy general and simple, they retain (for better or worse) discretion.