Law isn't code and it isn't crypto.
Judges aren't the only interpreters of law. They're simply the authoritative ones (ultimately). The law needs to be relatively authoritative so that people can make decisions around it. The whole process is actually a lot messier than such statements and there are usually valid arguments and evidence, but in general we should err on the side of least harm: which means if a law is poorly written, people might get away with something lawmakers wanted to stop. This can, and has, happened, and lawmakers deal with it by updating the law or crafting new ones. (Of course, I also think there is a distinction between the 'intent' of a law and what lawmakers intended and I really only object to basing decisions on the latter.)
Why? Because if an interpreter screws up, we update its code (or ours); but if a person screws up, we throw them in prison or fine them potentially devastating amounts. A person ought to be reasonably secure in acting in accordance with the law.
