Leeway for human interpretation of laws is not a bug, it's a feature. It doesn't make things bad laws.
This was the whole problem with the ludicrous "code is law!" movement a handful of years ago. No, it's not, law is made for people, life is imprecise and fairness and decency are not easy to encode.
Really, there are three parts to a judgement: facts, the law, and the application of them. There should be no leeway in determining what the law says about a given situation. If that is not decidable, it is a bug. However, what a fair judgement is given the facts and the law, is really a separate issue. You can introduce measures to give clear guidance what the law says, and still give judges flexibility. One of the upsides of "code is law" in that respect is being able to provide a clear statement of what the law says and require the judge to then explain in their judgement why that justifies or does not justify a given judgement.
A lot of bad judgement might be a lot more blatant (or not happen) if the judge had to justify outright ignoring the law.
How is that different from saying prejudice and cronyism is a feature?