Let's assume I agree with what you say. It still doesn't explain why people go through years of training, examinations and tests just because some parts are unclear on purpose.
Most states require a law degree to be an attorney, but according to Wikipedia "Until the late 19th century, law schools were uncommon in the United States. Most people entered the legal profession through reading law, a form of independent study or apprenticeship, often under the supervision of an experienced attorney." Wikipedia indicates Abraham Lincoln was a self taught lawyer.
Since the requirement has changed but our language hasn't I don't know that the requirement tells you must about the language.
Since the requirement has changed but our language hasn't I don't know that the requirement tells you must about the language.