In my view, the judiciary should be at least somewhat active in interpreting the law. By doing so, it fulfills its constitutional role.
One of the major roles of the judiciary is to check the elected branches. The judiciary needs to make sure that the other branches do not step over the line and make laws that violate the Constitution. If the judicial branch were to defer to the legislature too much, it would essentially be giving up that ability. The judicial branch has to stand up to the elected branches whenever it feels the Constitution is being violated.
If the judiciary is too passive, it risks allowing the elected branches to infringe on our liberties. Therefore, it needs to be active.