The JD is a three-year degree that is the first one earned in a subject. If that sounds like a bachelor's degree, it's because it really is: It used to be called an LLB or Bachelor of Laws. But law schools renamed it in a misguided attempt to increase the prestige of the legal profession. The only pretense it has to being called a graduate degree is that law schools require usually another bachelor's degree in a different subject. It's still a second bachelor's degree.
In short, the JD is a "doctorate" in name only. The legal community, for the most part, is wise enough not to push the matter.